- principle
- c.1380, "fundamental truth or proposition," from Anglo-Norm. principle, from O.Fr. principe, from L. principium (pl. principia) "a beginning, first part," from princeps (see prince). Meaning "origin, source" is attested from 1413. Sense of "general rule of conduct" is from c.1532. Used absolutely for (good or moral) principle from 1653.
"It is often easier to fight for principles than to live up to them." [Adlai Stevenson, speech, New York City, Aug. 27, 1952]
Hence principled "moral" (1697). Scientific sense of "general law of nature" is recorded from 1802.