Why is the ninth month called September?
also, through 18c., errour, c.1300, from Old French error "mistake, flaw, defect, heresy," from Latin errorem (nominative error) "a wandering, straying, mistake," from errare "to wander" (see err).
Words for "error" in most Indo-European languages originally meant "wander, go astray" (but cf. Irish dearmad "error," from dermat "a forgetting").
error er·ror (ěr'ər)
A defect or insufficiency in structure or function.
An act, an assertion, or a decision, especially one made in testing a hypothesis, that unintentionally deviates from what is correct, right, or true.