sub·woof·er 
(sŭbwf′ər)
(sŭbwf′ər)n.
A loudspeaker that is designed to produce sounds that are very low-pitched.
- photochemically
- photochemical smog
- photochemistry
- photochromatic
- photochromism
- photocoagulate
- photocoagulation
- photocompose
- photocomposition
- photoconduction
- photoconductive
- photoconductivity
- photocopier
- photocopy
- photocurrent
- photodecomposition
- photodegradable
- photodiode
- photodisintegration
- photoduplicate
- photoduplication
- photodynamic
- photodynamically
- photodynamics
- photodynamic therapy