As a child, I heard this song by Judy Collins and it was so haunting and the words so strange to an 11 year old child.
The album had been a gift to my mother from her friend Ross. To me, it was a song about clowns but it made no sense to me. Just surfing and found this little tidbit in Wikipedia.
Meaning of title
The "clowns" in the title do not refer to circus clowns (i.e. performers in the circus who wear white face with red noses). Instead, the "clowns" in the title are theatrical imagery, as Sondheim explained in a 1990 interview: "I get a lot of letters over the years asking what the title means and what the song's about".
In a 2008 interview, Sondheim further clarified the meaning:"As I think of it now, the song could have been called "Send In the Fools". I knew I was writing a song in which Desirée is saying, "aren't we foolish", or "aren't we fools"? Well, a synonym for fools is clowns. But Sondheim agreed that "Send In the Fools" lacked the same ring.
Around 20 years before the play begins, Desirée was a young, attractive woman, whose passions were the theater and men. She was a stage actress, and she lived her life dramatically, flitting from man to man. Fredrik was one of her many casual lovers, but he fell deeply in love with Desirée and asked her to marry him. Desirée refused his proposal, because she lived "in the air". When she refused, Fredrik abandoned the quest and left her. He did not know it when they parted, but Desirée was pregnant with his child.
A few months before the play begins, Fredrik fell in love and married a beautiful woman who is 18 years old – much younger than he. In Act One, Desirée and Fredrik meet after 20 years apart. Fredrik meets his and Desirée's love child, who is now a handsome young man, around 20 years old. Fredrik explains to Desirée that he is now married to the young woman, whom he loves, but she is still a virgin and refuses to have sex with him. Desirée seduces Fredrik, and they enjoy a passionate night together.
Act Two begins the next morning, and Desirée realizes that she truly loves Fredrik and that she should have married him so long ago. She tells Fredrik that he needs to be rescued from his marriage, and she proposes to him. She tells him that she needs to be rescued and asks if she too can rescue him. Fredrik explains to Desirée that he has been swept off the ground and is "in the air" in love with his beautiful, young wife. So Fredrik refuses Desirée's proposal, and he apologizes for having misled her. Fredrik walks across the room, while Desirée remains sitting on the bed. As she feels both intense sadness and anger, at herself, her life and her choices, she sings, "Send in the Clowns".
The lyrics of the song are written in four verses and a bridge and sung by Desirée. As Sondheim explains, Desirée experiences both deep regret and furious anger:
[“Send in the Clowns”] was never meant to be a soaring ballad. It’s a song of regret. And it’s a song of a lady who is too upset and too angry to speak – meaning to sing for a very long time. She is furious, but she doesn’t want to make a scene in front of Fredrik because she recognizes that his obsession with his 18-year-old wife is unbreakable. So she gives up. So it’s a song of regret and anger. And therefore fits in with short-breathed phrases.” 
 First Verse
The lyrics of the first verse introduce Desirée’s deep anger and regret.
Isn't it rich?
Are we a pair?
Me here at last on the ground,
You in mid-air.
Send in the clowns.
Isn’t it rich? This is a common theatrical expression, which in context means “our relationship has become so ironic”. The line and the entire song are sung with intense anger and hurt. Throughout the song, all questions are rhetorical: Desirée is not asking questions but is making rhetorical statements based on theatrical imagery. The word “rich” is emphasized in the dramatic song to highlight the bitter irony she feels.
Are we a pair? This is not question. Instead, it’s a rhetorical statement of anger and regret, which means, approximately, “Look at the two of us: how stupidly we have led our lives.” Recall that, just before this song in the drama, Desirée was rejected by Fredrik, and now she has abandoned her quest to be “a pair” with him. This song expresses that she is angry, sarcastic, bitter and sad at the situation in which she and he now find themselves.
Me here at last on the ground, Desirée has spent her life “in the air”, flitting from affair to affair. Now, however, she finally has her feet “at last on the ground” and wants to settle down with only one man: her long-ago lover, Fredrik.
You in mid-air. On the other hand, her previously grounded lover himself is now himself “in mid-air”: now madly in love with his new wife. So she sings these lines with anger and regret about the irony of their reversed roles.
Send in the clowns. The title is introduced. It means, “This is a theatrical performance so extremely bad that it can be saved only by bringing in comedy.”
 Second Verse
Isn't it bliss?
Don't you approve?
One who keeps tearing around,
One who can't move.
Where are the clowns?
Send in the clowns.
Isn't it bliss? Just like the word “rich” in the first verse, the word “bliss” here means irony and means the opposite of happiness. The word “bliss” is sung with an elongated “hiss” -- it drips with anger.
Don't you approve? Another rhetorical question, which in this case means “Surely you’re as unhappy with our relationship as I.”
One who keeps tearing around, This refers to Desirée herself. She is the one who has been running around with different lovers.
One who can't move. This is Fredrik, who has just recently been married to his young trophy wife.
Where are the clowns? Desirée means, “This play that is my life can be saved only by changing the performers”. The word “where” is smooth and elongated.
Send in the clowns. This is the theatrical expression. The closest lay expression may be “I don’t want to think about it anymore. Let’s change the subject”. As she sings the word “clowns”, she emphasizes the hard ‘k’ and makes the word almost two vowels (KUH – lowns).
Just when I'd stopped opening doors,
Finally knowing the one that I wanted was yours,
Making my entrance again with my usual flair,
Sure of my lines,
No one is there.
Just when I'd stopped opening doors, Desirée remembers that, after years of flitting from affair to affair (“opening doors”), she is now ready to “stop opening doors”.
Finally knowing the one that I wanted was yours, The important word is “that”, which does not mean “that person”. Instead, the word “that” refers to “that door”. The phrase, “knowing the one that I wanted was yours”, refers to the “door” to Fredrik’s heart and can be paraphrased: “finally I discovered that, after spending my life searching for true love, I know that you are my true love.”
Making my entrance again with my usual flair Desirée’s theatrical background as an actress is apparent in her expression about “making [her] entrance”, which she often does “with [her] usual flair”. Sondheim wrote the word “flair” itself to be sung with flair: "She is an actress, and she is used to sweeping in and out, so there is a certain amount of self-irony . . . ."
Sure of my lines Desirée uses another theatrical expression about being “sure of [her] lines”. she was sure that her proposal to Fredrik, which she made just before this song, would be successful, but . . .
No one is there. That is, after opening so many doors looking for true love, she finally came to her senses and opened “Fredrik’s door”, but he was not there – he rejected her, after so many previous times when Fredrik proposed to her, but she rejected him. Desirée is surprised, hurt, angry and full of regret – at herself and her situation. She is not angry at Fredrik but at herself. Desirée almost whispers the line, demonstrating that “no one is there”.
To paraphrase the bridge, “Just when I’d stopped looking for lovers, Finally realizing that I love only you, I came to you again, Sure that you would accept me as your lover, But you refused.”
 Third Verse
Don't you love farce?
My fault I fear.
I thought that you'd want what I want.
Sorry, my dear.
But where are the clowns?
Quick, send in the clowns.
Don't bother, they're here.
Don't you love farce? Like the first sentences of the previous verses, this is a rhetorical question that means, “My performance in my relationship with Fredrik is not a love story but a farce – a bitter tragedy.” Of course, “farce” is yet another of the many theatrical references that permeate the song. A farce is a type of comedy with improbable situations and often sexual innuendo, like her life.
My fault I fear. Of course, Desirée blames only herself.
I thought that you'd want what I want. Desirée believed that Fredrik would accept her as his true love, just as she is ready (finally) to accept him.
Sorry, my dear. Desirée is sorry for her mistaken belief. She is sorry for the situation she has created. As she sings, her self-loathing increases.
But where are the clowns? Desirée is asking rhetorically, “My performance is horrible.”
Quick, send in the clowns. This repeats the phrase. Sondheim instructs that the word “quick” should be sung quickly and with a clipped phrasing, because the "quick has an angry separation". This line is sung in complete contrast with the line in the fourth verse, “Well, maybe next year.” As she begins to sing the line at this point in the drama, Fredrik begins to walk toward Desirée, who until that point had been singing (thinking) to herself. As Fredrik approaches, she turns toward him and sings, in an angry, bitter manner . . .
Don't bother, they're here. Desirée almost spits out the word “bother” (often pronounced with a ‘b’ that sounds like ‘p’). She has turned the title (the theatrical expression) upside down. As she sees Fredrik walking toward her, she suddenly realizes that “her horrible life’s performance” results from its actors: herself and Fredrik.
The meaning of this last line requires an understanding of context. Sondheim explains that, in the drama, this is the last line, the climax and the entire point of the song. (Note that it is indeed the last line of the scene in the drama, as explained below.) In the previous scene, Desirée was rejected by Fredrik. In this scene, as she sings the song, she sings of her anger and regret. The scene ends as Fredrik walks toward her, and she sings the last line, which may be paraphrased as “Don’t bother to change the subject, because we ourselves are the subject: we are the horrible actors in this tragic, farcical performance – we are clowns”.
As she sings the last line of the fourth verse, she looks up and sees Fredrik. Therefore, the line, "Don't bother, they're here" makes sense.
After Desirée sings the angry line of regret, "Don't bother, they're here", Fredrik says the following to her: "I never should have come. I’m sorry. To flirt with rescue when one has no intention of being saved. Do try to forgive me." Judy Dench commented that this reference to "being saved" echoes Desirée's proposal to save Fredrik. Fredrik walks away from Desirée, who reprises the song.
 Fourth verse
Isn't it rich?
Isn't it queer,
Losing my timing this late
In my career?
And where are the clowns?
There ought to be clowns.
Well, maybe next year.
Isn't it rich? This repeats the opening line of the first verse. As there, Desirée means “This situation is so ironic”.
Isn't it queer, This echoes the first line and means “This situation is so absurd.”
Losing my timing this late This is another theatrical reference, which describes the irony of her realization, too late, of her love for Fredrik.
In my career? Another reference to her career as an actress: her entire life has been a theatrical performance.
And where are the clowns? Desirée wants to change the subject, to think of something other than her anger and regret.
There ought to be clowns. She repeats her desire for theatrical effect.
Well, maybe next year. The final line of this reprise adds a touch of hope that Desirée will find happiness. After the horrible performance that her life has been, she longs for, but she cannot find, something to save her life’s performance from this tragic farce. But Desirée does not abandon all hope -- she hopes that her life’s performance will be a success and that she will find true her love with Fredrik “maybe next year”. Sondheim teaches that the word "quick" in verse four has an angry separation, but the word "well" in this verse has a kind of resigned separation and should be sung almost as an interjection, not really part of the phrase