What does invagination mean?
Invagination is the process by which a flat sheet, membrane, or developmental tissue folds or turns inward, often creating a pouch, cavity, or tube. It is especially important in cell biology, where the cell membrane can invaginate to help form vesicles, and in embryology, where folding of the embryo’s surface contributes to the formation of internal tissues and organs. The word is more precise than a general expression such as “folding inward,” because it identifies a defined biological or developmental process. It also has a broader technical use for the inward fold itself. The related verb is “invaginate,” while “evagination” names the corresponding outward folding or outward growth. Invagination is therefore especially useful to readers studying anatomy, development, or the structural organization of cells.
nounThe folding or turning inward of a tissue, membrane, or organ to form a pouch, cavity, or tubular structure. In biology, it may also describe the developmental process in which part of an embryonic surface becomes enclosed within the body.
- The process of folding or turning inward, especially of a membrane or organ.
- The inward fold or pouch formed by such a process.
- In embryology, the process by which a surface becomes enclosed within the developing body.
"The cell membrane undergoes invagination, folding inward to help form a vesicle."
"Invagination of the cell membrane is an early step in vesicle formation."
"During embryonic development, invagination helps establish the body’s internal layers."
Usually used for multiple inward folds, structures, or instances of the process.
"Microscopic examination revealed several invaginations along the membrane."
Invagination is how a flat sheet of cells begins building three-dimensional organs: simply fold inward, and complexity follows.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does invagination come from?
The word comes from Latin invaginare, meaning “to put into a sheath or fold inward,” formed from in- (“into”) and vagina (“sheath”). English borrowed the noun in the early 19th century for the inward folding of tissues and organs. Its principal cognate in biological terminology is evagination, from evaginare, which refers to the opposite process of folding or growing outward.
Related word forms
How invagination is actually used
This is primarily a technical term used in biology, anatomy, and embryology. In general writing, it is less common than the plainer phrase “folding inward.”
Easily confused with invagination
Invagination is a folding or growth inward, whereas evagination is a folding or growth outward.
Intussusception is the telescoping of one section of intestine into another, whereas invagination is the general process of a tissue or membrane folding inward.