aorist (n.)

1580s, the tense of Greek verbs that most closely corresponds to the simple past in English, from Greek aoristos (khronos) "indefinite (tense)," from aoristos "without boundaries, undefined, indefinite," from assimilated form of a- "not" (see a- (3)) + horistos "limited, defined," verbal adjective from horizein "to limit, define," from horos "boundary, limit, border" (see horizon). Related: Aoristic.