Medicine & BodyGreek → English
Blastocyst
/ˈblastə(ʊ)sɪst/noun
The hollow ball of cells an early mammalian embryo forms around day five, before it implants in the uterine wall.
The Greek roots
βλαστός
blastós
sprout, germ
κύστις
kýstis
bladder, pouch
Literally: “sprout bladder”
The story of the word
Greek βλαστός is a plant word, the shoot pushing out of a seed, and nineteenth-century embryologists reached for it because early animal development looked like budding. The κύστις half names the fluid-filled cavity that gives the stage its shape, the same word behind cystitis. Everything a person becomes is decided in that hollow sphere: the outer layer goes on to build the placenta, the inner clump becomes the body.
- How it travelled
- Ancient Greek → scientific coinage → English
- First recorded
- 19th century
Same family
blastulacystitisfibroblasttrophoblast
In a sentence
Two blastocysts were frozen for a later cycle.
At the blastocyst stage the cells have already split into two distinct populations.