'Oracle' literally means 'that which speaks' — from Latin 'os' (mouth). Kin to 'oral' and, oddly, 'adore.'
A priest or priestess through whom a deity is believed to speak; a prophetic utterance; a source of authoritative wisdom.
From Old French 'oracle,' from Latin 'ōrāculum' (a divine announcement, a prophetic declaration, the place where prophecy is given), from 'ōrāre' (to speak, to pray, to plead), from 'ōs' (mouth, face), from PIE *h₃éh₁os (mouth). An oracle is literally 'that which speaks' — or more precisely, 'a little speaking,' the diminutive suffix '-culum' suggesting the intimate, whispered quality of divine communication. The same root produced 'oral,' 'oration,' and
The word 'adore' is a hidden relative of 'oracle.' Latin 'adōrāre' meant 'to pray to, to speak to (a god)' — from 'ad-' (to) + 'ōrāre' (to speak, to pray). To adore someone was originally to pray to them, to address them as divine. And 'inexorable' (that which cannot be moved by prayer) comes from 'in-' + 'ex-' + 'ōrāre' — literally 'un-pray-out-able.'