trap·door 
(trăpdôr)
(trăpdôr)n.
A hinged or sliding door in a floor, roof, or ceiling.
- photoemission
- photoemission spectroscopy
- photoengrave
- photoengraver
- photoengraving
- photo-essay
- photo essay
- photo-essayist
- photo finish
- photoflash
- photoflood
- photofluorogram
- photofluorographic
- photofluorography
- photog
- photogelatin process
- photogene
- photogenic
- photogenically
- photogram
- photogrammetric
- photogrammetrist
- photogrammetry
- photograph
- photographable