The perfect tense of a verb meaning 'to see,' but functioning with present meaning: 'I know' (because I have seen). This is Greek's primary verb for knowledge—not theoretical but experiential, rooted in perception. The full paradigm includes an aorist εἶδον ('I saw') used as past tense for ὁράω, and this perfect οἶδα ('I know') with present force. The pattern reflects Proto-Indo-European roots shared with Latin video and Germanic 'wit.' Biblical writers employ it for knowledge of God, awareness of facts, and recognition of truth. Paul contrasts knowing in part with knowing fully. Jesus asks, 'Do you know what I have done for you?' The verb assumes knowledge comes through sight—or divine revelation that counts as seeing.