Sage comes directly from the Latin sapere, to know, shared by both the English word for wisdom and the herb long associated with clear-headed judgment. The name states its meaning plainly -- discernment named outright rather than implied through symbol or story.
You must take in consideration that two opposite stars reinforce each other in the rulership of human beings, unlike the stars of fate. And this is what we take in consideration of all that was said by that man. - Picatrix (Andalusia, ~1000.AD)