ḱerd-yo-
“to believe, to trust”believe, trust, credit
Compound of heart-root + *dheh1-, yielding Latin credere, English creed.
Discussion
The form *ḱerd-yo- represents a denominative derivation from the Proto-Indo-European root *ḱerd- (heart), extended with the suffix *-yo- to create a verbal sense of "placing one's heart in," hence "to believe" or "to trust." The principal descendant is Latin crēdere (to believe, to entrust), which arose from an old compound *ḱred-dʰeh₁-, literally "to place one's heart," combining the heart-root with *dʰeh₁- (to put, to place). This compound is treated more fully under *ḱred- (see the full treatment there). The present entry records the variant reconstruction that emphasizes the adjectival or denominative formation in *-yo-. The Latin verb produced an extraordinary range of English vocabulary: creed (from crēdō, "I believe"), credit and its derivatives creditor, accredit, and discredit, the adjective credible with incredible and credulous, and the theological term credo itself. Through Old French, crēdere also yielded grant (from *crēdentāre, to entrust), demonstrating how far phonological change can carry a word from its etymological origins. Whether one reconstructs the proto-form as a compound *ḱred-dʰeh₁- or a suffixed derivative *ḱerd-yo-, the semantic core remains identical: belief in the Indo-European world was an act of the heart, not of the mind, a conception that persists in modern English phrases like "heartfelt conviction" and in the very word courage, which descends from Latin cor (heart) through Old French.
Notes
Pokorny 580. English creed, credit, incredible, grant (via Old French).