Etymology Learned borrowing from Latin dexter (“right”).
1
Right; on the right-hand side. (In heraldry, specifically the bearer's right, which is the viewer's left.)
Archaic outside heraldry
my Mothers bloud / Runs on the dexter checke, and this ſiniſter / Bounds in my fathers:c. 1602 (date written), William Shakespeare, “The Tragedie of Troylus and Cressida”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act V, scene v], column 2:
Displaying his dexter palm, he exclaimed that there was a hand that never took a bribe; whereupon a smart auditor cried "How about the one behind your back?"1887, George William Foote with J. M. Wheeler, Crimes of Christianity, London: Progressive Publishing:
3 more examples
Clovis wiped the trace of Turkish coffee and the beginnings of a smile from his lips, and slowly lowered his dexter eyelid.1911, Saki, ‘The Match-Maker’, The Chronicles of Clovis:
The shield was divided into five, with two coats of arms on the dexter side (the right-hand side from the point of view of the bearer of the shield)—London and Southampton—and three on the sinister side—Salisbury, Winchester and Portsmouth.1956 July, Col. H. C. B. Rogers, “Railway Heraldry”, in Railway Magazine, page 477:
[…] the dexter lion being gorged […]1998 July 6, Auguste Vachon, Claire Boudreau, Daniel Cogné, Genealogica & Heraldica: Ottawa 1996, University of Ottawa Press, →ISBN, page 324:
Etymology Learned borrowing from Latin dexter (“right”).
1
The right side (of a building, an equation, a heraldic shield [from the wearer's perspective], etc).
Archaic outside heraldry
Subtracting the second from the first, the third from the second and the first from the third successively, we obtain, after transposition, the following identities: — [several equations] But, the sinisters being exact differentials, the dexters are so. Consequently [...]1879, London Mathematical Society, Proceedings of the London Mathematical Society, page 112:
On the dexter of the court is a long hall with an arched ceiling and a door, leading to a small oblong shrine with a vaulted ceiling.1971, Debala Mitra, Buddhist Monuments:
One of a breed of small hardy cattle originating from the Kerry breed of Ireland, valuable for beef and milk. They are usually chiefly black, sometimes red, and somewhat resemble a small shorthorn in build.