I. (ˈ)nep|t(y)ünēən sometimes -|chü- adjective
Etymology: Latin neptuni us Neptunian (from Neptunus ) + English -an
1. usually capitalized : of or relating to the god Neptune, the planet Neptune, or the ocean
2.
a. : formed by the agency of water
b. : of or relating to neptunism or the neptunists
II. noun
( -s )
: neptunist