- optimum
- 1879, from L. optimum, neut. sing. of optimus "best" (used as a superl. of bonus "good"), probably related to ops "power, resources" (in which case the evolution is from "richest" to "the most esteemed") or to ob "in front of," with superlative suffix *-tumos. Originally in biology, in ref. to "conditions most favorable" (for growth, etc.).