"examine a witness (by the other side) to 'check' the effects of previous questioning," 1660s, from cross (adv.) in the sense "proceeding from an adverse party by way of reciprocal contest" + examine. Related: Cross-examination (1746).
cross-country
cross-current
cross-cut
cross-dressing
crossed
cross-examine
cross-eyes
cross-fire
cross-hair
crossing
cross-legged