～か月
～かげつ · ～kagetsu · JLPT N5 · noun
calendar month
📅 か月 = counter ka + 月 moon/month: a count of moons
月 means moon, and a month is one moon cycle. Read げつ (getsu) here, as in 月曜日 getsuyoubi, Monday = moon day. Put a number in front: 三か月 sankagetsu = three months. か is the counting particle, also written ヶ or 箇.
月 — pictograph of crescent moon
月 is a pictograph of a crescent moon, chosen over a full circle to distinguish it from 日 (sun). The inner strokes originally depicted the moon's shadow or markings. As a radical it often relates to the moon, time, or (via a lookalike form of 肉 'flesh') body parts.