What is meant by the seven ages of man?

The seven ages of man are the seven developmental stages of a person's life, as outlined by William Shakespeare in "As You Like It." Specifically, in Act II, Scene 7, the character of Jacque describes the world as a stage and "all the men and women merely players," before going on to say that each man plays seven parts in his time.

These seven parts, acts or ages are defined in the play as follows:

1. The infant, "mewling and puking in the nurse's arms"
2. The whining school-boy, "with his satchel and shining morning face, creeping like a snail unwillingly to school"
3. The lover, "sighing like furnace, with a woeful ballad made to his mistress' eyebrow"
4. The soldier, "full of strange oaths, and bearded like the pard" ("pard" meaning leopard)
5. The justice, "in fair round belly with good capon lin'd, with eyes severe and beard of formal cut" ('with good capon lin'd' meaning well-fed or stuffed on fattened chicken)
6. The lean and slipper'd pantaloon (or foolish old man), "with spectacles on nose and pouch on side ... his big manly voice, turning again toward childish treble"
7. Second childishness and mere oblivion (senility and death), "sans teeth, sans eyes, sans taste, sans everything"

Shakespeare's rubric closely follows that of several premodern European thinkers, including Isidore of Seville, who categorized the stages of life by age ranges, from birth to around 70 and death.