axiom (n.)
late 15c., from Middle French axiome, from Latin axioma, from Greek axioma "authority," literally "that which is thought worthy or fit," from axioun "to think worthy," from axios "worthy, worth, of like value, weighing as much," from PIE adjective *ag-ty-o- "weighty," from root *ag- "to drive, draw, move" (see act (n.)).
Axioms in philosophy are not axioms until they are proved upon our pulses. [Keats, letter, May 3, 1818]