/ Dictionary / Index A arcus senilis: Meaning and Definition of Find definitions for: ar•cus se•ni•lis Pronunciation: (är'kus su-nī'lis), [key] — Ophthalm. Ophthalm. the appearance of a yellowish-gray lipid ring around the margin of the cornea, occurring in aging persons. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. arcus arc welding Related Content Daily Word Quiz: confectionery Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language