The Collaborative International Dictionary
Dextro-
Dextro- \Dex"tro-\ A prefix, from L. dexter, meaning, pertaining to, or toward, the right; (Chem. & Opt.) having the property of turning the plane of polarized light to the right; as, dextrotartaric acid.
Douglas Harper's Etymology Dictionary
dextro-
word-forming element meaning "toward or on the right-hand side," from comb. form of Latin dexter (see dexterity).
Wiktionary
dextro-
pre. (context chemistry English) Denoting a dextrorotatory form of an enantiomer.