tet·rad 
(tĕtrăd′)
(tĕtrăd′)n.
1. A group or set of four.
2. A tetravalent atom, radical, or element.
3. Biology
a. A four-part structure that forms during the prophase of meiosis and consists of two homologous chromosomes, each composed of two sister chromatids.
b. A group of four haploid cells, such as spores, formed by meiotic division of one mother cell.
[Greek tetras, tetrad-; see kwetwer- in the Appendix of Indo-European roots.]
te·tradic adj.
- fumigator
- Fumimaro
- fumitory
- Fumé Blanc
- fun
- Funafuti
- funambulism
- funambulist
- function
- functional
- functional food
- functional group
- functional illiterate
- functionalism
- functional isomer
- functionalist
- functionality
- functionally
- functional magnetic resonance imaging
- functional neurological symptom disorder
- functional shift
- functionary
- function key
- functionless
- function word