a group of four cells formed by meiosis from one diploid cell
4. genetics
a four-stranded structure, formed during the pachytene stage of meiosis, consisting of paired homologous chromosomes that have each divided into two chromatids
5. chemistry
an element, atom, group, or ion with a valency of four
6. ecology
a square of 2 × 2 km used in distribution mapping
Word origin
C17: from Greek tetras, from tettares four
tetrad in American English
(ˈtɛˌtræd)
noun
1.
a group or set of four
2. Botany
a group of four cells formed by division within a spore mother cell during meiosis
3. Chemistry
an atom, radical, or element that is tetravalent
4. Genetics
a group of four similar chromatids formed by the longitudinal division of a pair of homologous chromosomes during meiotic prophase