late 14c. (late 13c. as a surname), an old name for the pole star (compare Old Norse leiðarstjarna) as the star that "leads the way" in navigation; from lode (n.) + star (n.). Figurative use from late 14c.
"magnetically polarized oxide of iron," 1510s, literally "way-stone," from lode + stone (n.). So called because it was used to make compass magnets to guide mariners. Figurative use from 1570s.