sage (n.1) Look up sage at Dictionary.com
kind of herb (Salvia officinalis), early 14c., from Old French sauge (13c.), from Latin salvia, from salvus "healthy" (see safe (adj.)). So called for its healing or preserving qualities (it was used to keep teeth clean and relieve sore gums, and boiled in water to make a drink to alleviate arthritis). In English folklore, sage, like parsley, is said to grow best where the wife is dominant. In late Old English as salvie, directly from Latin. Compare German Salbei, also from Latin.
sage (adj.) Look up sage at Dictionary.com
"wise," c.1300 (late 12c. as a surname), from Old French sage "wise, knowledgeable, learned; shrewd, skillful" (11c.), from Gallo-Roman *sabius, from Vulgar Latin *sapius, from Latin sapere "have a taste, have good taste, be wise," from PIE root *sap- "to taste" (see sap (n.1)). Meaning "characterized by wisdom" is from 1530s. Related: Sageness.
sage (n.2) Look up sage at Dictionary.com
"man of profound wisdom," mid-14c., from sage (adj.). Originally applied to the Seven Sages -- Thales, Solon, Periander, Cleobulus, Chilon, Bias, and Pittacus.