Definition of "ocular"

The eyes of men converse as much as their tongues, with the advantage, that the ocular dialect needs no dictionary, but is understood all the world over.

1860, Ralph Waldo Emerson, “Behavior”, in The Conduct of Life‎, Boston: Ticknor & Fields, page 156

Villain, be sure thou prove my love a whore,Be sure of it; give me the ocular proof:Or by the worth of man’s eternal soul,Thou hadst been better have been born a dogThan answer my waked wrath!

c. 1603–1604 (date written), William Shakespeare, “The Tragedie of Othello, the Moore of Venice”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene iii]

For as Thomas was an ocular Witness of Christ’s Death and Burial, so were the other Disciples of his Resurrection; having actually seen him after he was risen.

1692, Robert South, “A Discourse concerning Our Saviour’s Resurrection”, in Sermons Preached upon Several Occasions‎, 6th edition, volume V, London: Jonah Bowyer, page 171

[…] I should have been apt to think, that the young gentlewomen and Mr. Lovelace were of longer acquaintance than yesterday. For he, by stealth, as it were, cast glances sometimes at them, which they returned; and, on my ocular notice, their eyes fell, as I may say, under my eye, as if they could not stand its examination.

1748, [Samuel Richardson], “Letter LXIII”, in Clarissa. Or, The History of a Young Lady: […], volume III, London: […] S[amuel] Richardson; […], page 300

Captain Lincoln proceeded to relate some of the strange fables and fantasies, which, as it was impossible to refute them by ocular demonstration, had grown to be articles of popular belief, in reference to this old picture.

1842, Nathaniel Hawthorne, “Edward Randolph’s Portrait”, in Twice-Told Tales‎, volume 2, Boston: James Munroe, page 32

Suddenly starting from a proposition, exactly and sharply defined, in terms of utmost simplicity and clearness, he rejected the forms of customary logic, and by a crystalline process of accretion, built up his ocular demonstrations in forms of gloomiest and ghastliest grandeur, […]

1849 October 20, Nathaniel Parker Willis, “Death of Edgar Poe”, in Home Journal‎