royal tax in medieval England, c.1600, as a historical term, from Medieval Latin geldum, from Old English gield "payment, tax, tribute, compensation," from Proto-Germanic *geldam "payment" (cognates: Middle High German gelt "payment, contribution," German geld "money," Old Norse gjald "payment," Gothic gild "tribute, tax"), from PIE root *gheldh- "to pay" (see yield, v.).

"to castrate," c.1300, from Old Norse gelda "to castrate," said in Watkins to be from Proto-Germanic *galdjan "to castrate," from PIE *ghel- (3) "to cut." Related to other words which, if the derivation is correct, indicate a general sense of "barren." Compare Old Norse geld-fe "barren sheep" and geldr (adj.) "barren, yielding no milk, dry," which yielded Middle English geld "barren" (of women and female animals); also Old High German galt "barren," said of a cow. Related: Gelded; gelding.