| an extraordinary or unusual thing, person, or event; an exceptional example or instance. |
| a screen or mat covered with a dark material for shielding a camera lens from excess light or glare. |
invagination in·vag·i·na·tion (ĭn-vāj'ə-nā'shən)
n.
The act or process of invaginating or the condition of being invaginated.
An invaginated organ or part.
The infolding of a portion of the outer layer of a blastula in the formation of a gastrula.