fall asleep(redirected from fallen asleep)
1. To yield to tiredness and begin to sleep. Please don't make too much noise—the baby has finally fallen asleep.
2. euphemism To die. We told the kids the bad news that Pop-Pop fell asleep last night.
Fig. to go to sleep. I fell asleep while reading the very dull book. I got in bed and fell asleep at once.
Go to sleep; also, cease paying attention. For example, As soon as the lights were dimmed he fell asleep, or His lectures are so dull that I fall asleep. The literal usage, which uses the verb fall in the sense of "succumb," dates from about 1300; the figurative is several centuries newer. Also see asleep at the switch.