pentad
英 ['pentæd]
美 ['pentæd]
- n. 五；五个一组；五年间；五价物
英语词源
- pentad (n.)
- 1650s, from Greek pentas (genitive pentados) "group of five" (see five). Meaning "period of five years" is from 1880; meaning "period of five days" is from 1906, originally in meteorology.