Main Entry: he·li·coid

Pronunciation: \ˈhe-lə-ˌkȯid, ˈhē-\

Variant(s): or he·li·coi·dal \ˌhe-lə-ˈkȯi-d^əl, ˌhē-\

Function: adjective

Date: circa 1704

1 : forming or arranged in a spiral
2 : having the form of a flat coil or flattened spiral <helicoid snail shell>