| Neocomian | n. [ From Neocomium, the Latin name of Neuchatel, in Switzerland, where these rocks occur. ] (Geol.) A term applied to the lowest deposits of the Cretaceous or chalk formation of Europe, being the lower greensand. [ 1913 Webster ] |
| Neocomian | a. (Geol.) Of or pertaining to the lower greensand. [ 1913 Webster ] |