To distinguish by some ornament or symbol.
- Nuttall's Standard dictionary of the English language. By Nuttall, P.Austin. Published 1914. (verb) (v.) (verb)
The banner or flag of a regiment; the infantry officer who carries the flag of a regiment; a mark of rank or office; the national flag of a ship.
- Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874. (noun) (n.) (noun)
The flag, banner, or standard of a regiment or a nation; any signal to give notice; a mark of distinction, rank, or office: formerly a commissioned officer of the lowest rank in a company of infantry, the senior of whom carried the regimental colours. Naval ensign, a large banner hoisted on a staff, over the stern of a ship, or at the gaff, when the ship is under sail, for the purpose chiefly of distinguishing the nationality.
- Nuttall's Standard dictionary of the English language. By Nuttall, P.Austin. Published 1914. (noun) (n.) (noun)
A standard; the officer who carries it.
- The Clarendon dictionary. By William Hand Browne, Samuel Stehman Haldeman. Published 1894. (noun) (n.) (noun)
A flag; badge; the lowest rank of commissioned officer in the navy.
- The Winston Simplified Dictionary. By William Dodge Lewis, Edgar Arthur Singer. Published 1919. (noun) (n.) (noun)
The sign or flag distinguishing a nation or a regiment: formerly the junior subaltern rank of commissioned officers of the British infantry, so called from bearing the colors.
- The american dictionary of the english language. By Daniel Lyons. Published 1899. (noun) (n.) (noun)

Usage examples:

The ensign who carried them was wounded, and already a score of the enemy were rushing forward to seize the prize and carry it off in triumph to their king.
- The Adventures of a Three-Guinea Watch by Talbot Baines Reed
When he returned, Florette had vanished; " run after the ensign people said, and they were right.
- The Complete Historical Romances of Georg Ebers by Georg Ebers
" Never say die," warned Ensign Eph Somers seriously, " until you know you're really dead!"
- Dave Darrin's Fourth Year at Annapolis by H. Irving Hancock