diction (n.) Look up diction at Dictionary.com
1540s, "a word;" 1580s, "expression of ideas in words," from Late Latin dictionem (nominative dictio) "a saying, expression, word," noun of action from dic-, past participle stem of Latin dicere "speak, tell, say" (source of French dire "to say"), related to dicare "proclaim, dedicate," from PIE root *deik- "to point out" (cognates: Sanskrit dic- "point out, show," Greek deiknynai "to show, to prove," Latin digitus "finger," Old High German zeigon, German zeigen "to show," Old English teon "to accuse," tæcan "to teach").

Another cognate is Greek dike "custom, usage," and, via the notion of "right as dependent on custom," "law, a right; a judgment; a lawsuit, court case, trial; penalty awarded by a judge."