villus(redirected from arachnoid villus)
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1. Zoology anatomy any of the numerous finger-like projections of the mucous membrane lining the small intestine of many vertebrates
2. any similar membranous process, such as any of those in the mammalian placenta
3. Botany any of various hairlike outgrowths, as from the stem of a moss
A fingerlike projection from the surface of a membrane.