交じる
まじる · majiru · JLPT N3 · verb-godan
to mingle with
👥 交 = cross, as in 交差点 (crossing): paths cross and people mingle
交じる is for things that mix but stay separate, like one child among adults or white hairs among black. 混じる is for things that blend completely. Both read まじる. The ma- sound gives a hook too: majiru mixes.
交 — top 亠 + 父-like crossed legs
Originally a pictograph of a person standing with legs crossed, showing the idea of crossing or intersecting. From this concrete image, the meaning extended to abstract senses like 'exchange,' 'interact,' and 'hand over.' Modern uses such as 交流 (exchange) and 交通 (traffic) all trace back to this core notion of crossing.