Definition of "dropout"

dropout

noun
countable and uncountable, plural dropouts
1. Someone who has left an educational institution without completing the course
2. Someone who has opted out of conventional society.
3. One who suddenly leaves anything, or the act of doing so.
  Quotations
  To avoid excessive dropouts from the study, we wouldn't employ a single tutored group and a single control group that received no instruction at all.
  2010, R. Barker Bausell, Too Simple to Fail: A Case for Educational Change, page 193
4. (cycling) The slot in the frame that accepts the axles of the wheels.
5. A damaged portion of a tape or disk, causing a brief omission of audio, video, or data.
6. Momentary loss of an electronic signal.
7. A technique for regularizing a neural network by discarding a random subset of its units.