The Glass Menagerie, written by Tennessee Williams in 1944, derives its title from the collection of small glass animals that belongs to Laura Wingfield, an extremely frail, shy, and reclusive young woman, who spends most of her time attending to her glass collection.
The glass animals are symbolic of Laura's physical and emotional fragility. Laura is physically disabled—according to Williams's character description, "one leg slightly shorter than the other, and held in a brace"—and she lives in her own world of loneliness, dreams, and imagination, almost wholly estranged from reality.
Laura is self-conscious, has a strong sense of inferiority, and finds it almost impossible to come to terms with the world in which she lives, either within her own family or in the world at large. As her brother Tom says, "She lives in a world of her own―a world of―little glass ornaments...She plays old phonograph records and—that's about all" (scene 5).
The play of The Glass Menagerie evolved from a short story, "Portrait of a Girl in Glass," which Williams wrote in 1941 and which provides further insight into Laura's character. In the short story, Tom says about Laura,
She made no positive motion toward the world but stood at the edge of the water, so to speak, with feet that anticipated too much cold to move.
In scene 6 of the play, Jim O'Connor, one of Tom's high school classmates and now a coworker, "the only one at the warehouse with whom I was on friendly terms," (scene 6) comes to dinner at the Wingfield's house. Laura remembers Jim as the only boy she liked in high school, although he barely knew she existed, and she's too overwhelmed to sit at the dinner table with him.
After dinner, Laura overcomes her shyness to sit alone with Jim on the couch in the living room and reminisce about high school, and she shows him her glass animal collection. "Mother calls them a glass menagerie!" she says (scene 7). Laura lets Jim hold her favorite, a unicorn.
JIM: Unicorns, aren't they extinct in the modern world?
LAURA: I know!
JIM: Poor little fellow, he must feel sort of lonesome (scene 7).
Jim later kisses Laura and even talks her into dancing with him, but during their dance they bump into a table and knock the unicorn to the floor, breaking the horn off the glass animal.
LAURA. I'll just imagine he had an operation. The horn was removed to make him feel less—freakish !
[They both laugh.] Now he will feel more at home with the other horses, the ones that don't have horns (scene 7).
The symbolism of the broken unicorn becomes clear when Jim tells Laura that he's engaged to be married, and is further emphasized when Laura gives Jim the broken unicorn as "a souvenir" (scene 7), a symbol of her broken heart and her broken life.
Laura then retreats into her own familiar world. "She rises unsteadily and crouches beside the Victrola to wind it up" (Stage directions, scene 7) and doesn't say another word to Jim.