Forty Winks Meaning

(idiomatic) A short sleep, an extra sleep, a nap.

Example:   As you're so tired, why not try to catch "forty winks" before you leave?.
1922, James Joyce, Ulysses, Episode 16
  ...who evidently a glutton for work, it struck him, was having a quiet forty winks for all intents and purposes on his own private account while Dublin slept.