小于
xiǎo yú · HSK 6
less than
📉 小 (small) + 于 (than) — literally small-than, i.e. less than
于 acts as the comparison word than. So 大于 means greater-than and 小于 means less-than — a neat symmetric pair to learn together.
小 — three small strokes around a central vertical
小 is a pictograph originally showing three tiny dots or specks, suggesting small particles or grains. Over time the dots became stylized strokes flanking a central line. The core meaning 'small' has stayed remarkably stable from oracle bone script to today.
于 — two horizontal strokes 二 + vertical hook 亅
于 originated as a pictograph of breath or sound flowing outward, depicting exhalation through a passage. In oracle bone script it resembled a curved line showing motion or extension. Over time it became a grammatical preposition meaning 'at,' 'in,' or 'to,' losing its original concrete sense.