An Etymological Dictionary of Astronomy and Astrophysics

The notion that any hypothesis should be stripped of all unnecessary assumptions. If two hypotheses fit the observations equally well, the one that makes the fewest assumptions should be chosen.

Etymology (EN): The doctrine was formulated by William of Ockham (c.1288-c.1347),
an English Franciscan friar and scholastic philosopher. Razor from O.Fr. rasour “a razor,” from raser “to scrape, shave.”

Etymology (PE): Ostaré “razor,” from sotordan “to shave, erase, remove;”
Mid.Pers. ôstarak “removed, shaved,” ôstârišn “wiping, shaving;”
cf. Khotanese ustar- “to remove,” Sogdian (prefixed *pari-) prtr- “to wipe off, dry up,”
from Proto-Iranian *us-tar- “to remove, wipe off.”