hy·drog·e·nase 
(hī-drŏjə-nās′, -nāz′)
(hī-drŏjə-nās′, -nāz′)n.
An enzyme in certain microorganisms that catalyzes the hydrolysis or reduction of a substrate by molecular hydrogen.
- Fourier analysis
- Fourierism
- Fourierist
- Fourierite
- Fourier series
- Fourier transform
- four-in-hand
- four-leaf clover
- four-letter word
- four-o'clock
- four-peat
- fourpenny nail
- fourplex
- four-poster
- fourragère
- fourscore
- foursome
- foursquare
- foursquarely
- four-star
- fourteen
- fourteenth
- fourth
- fourth dimension
- fourth estate