Meaning of drop seat

drop' seat"

Pronunciation: [key]
  1. a hinged seat, as in a taxicab or bus, that may be pulled down for use when an additional seat is needed.
  2. a rear panel, as on long one-piece underwear or children's pajamas, that may be opened and lowered separately.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.