ret·ro·el·e·ment 
(rĕt′rō-ĕlə-mənt)
(rĕt′rō-ĕlə-mənt)n.
A genetic element, such as a retrotransposon, that can be incorporated into a DNA sequence after reverse transcription of an RNA molecule.
- fourgon
- fourhanded
- Four-H Club
- Four Horsemen of the Apocalypse
- Four Hundred
- Fourier
- 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