| Tithonic | a. [ L. Tithonius belonging to Tithonus, the consort of Aurora, Gr. &unr_;. ] Of, pertaining to, or denoting, those rays of light which produce chemical effects; actinic. [ R. ] [ 1913 Webster ] |
| Tithonicity | n. (Chem. & Physics) The state or property of being tithonic; actinism. [ R. ] [ 1913 Webster ] |