To move back and forth across something in a pattern of crossing lines; to cross each other at angles; a pattern of intersecting lines.
From 'Christ-cross' (a Christian cross), from the 1600s as a children's term, eventually shortened and used to describe any X-shaped crossing pattern.
The word 'crisscross' is a reduplication (a sound repeated in different forms), and so many of these exist in English—zigzag, tick-tock, flip-flop—which reveals that our brains find repetitive patterns easier to remember and more satisfying to say.
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