名詞 invagination:

1. the condition of being folded inward or sheathed
   同義詞：introversion
2. the folding in of an outer layer so as to form a pocket in the surface
   同義詞：introversion, intussusception, infolding

in.vag.i.na.tion

n.（名詞）
The act or process of invaginating or the condition of being invaginated.
入鞘：使入鞘的動作或過程或被裝入鞘中的狀態(tài)
An invaginated organ or part.
縮入部分：反折的器官或部分
Embryology The infolding of a portion of the outer layer of a blastula in the formation of a gastrula.
【胚胎學】 腸套疊：在原腸胚形成過程中囊胚的外層的折疊部分