Fraunhofer (diffraction) hologram
Fraunhofer holography
fraxinella
fray
fraying
fraze
frazil
frazzle
freak
freak out
freak-out
freaked
freakish
freakishly
freakishness
freaky
freckle
freckled
freckly
free
free agent
free-and-easy
free association
free-board
free-born
free charge
free church
free-cutting
free electron
free enterprise