- photomicroscope
- photomontage
- photomultiplier
- photomultiplier tube
- photomural
- photon
- photonegative
- photonics
- photons
- photonuclear
- photo-offset
- photo opportunity
- photoperiod
- photoperiodical
- photoperiodicities
- photoperiodicity
- photoperiodism
- photoperiodisms
- photophile
- photophilic
- photophilous
- photophobe
- photophobia
- photophobic
- photophore