1. (a.) Of or pertaining to the ocean or sea.
2. (a.) Formed by water or aqueous solution; as, Neptunian rocks.
3. (n.) Alt. of Neptunist.
| Neptunian 1. (a.) Of or pertaining to the ocean or sea. 2. (a.) Formed by water or aqueous solution; as, Neptunian rocks. 3. (n.) Alt. of Neptunist. | |