epiboly

詳細解釋：

e.pib.o.ly

n.Embryology （名詞）【胚胎學】
The growth of a rapidly dividing group of cells around a more slowly dividing group of cells, as in the formation of a gastrula.
外包：在胚胎的形成中，一部分分裂快的細胞的生長包圍另一部分生長慢的細胞

來源：
Greek epibolô [a throwing or laying on]
希臘語 epibolô [擴散或增長]
from epiballein [to throw on]
源自 epiballein [猛攻]
epi- [epi-]
epi- [在…周圍]
ballein [to throw] * see g wel…-
ballein [扔] *參見 g wel…-

【引伸】
ep.ibol.ic