低于
dīyū · HSK 5
be lower than
⬇️ 低 = low + 于 = than/at; literally 'low-than' = be lower than
低 means low; 于 is a classical particle marking comparison or location, like 'than' or 'at'. Together 低于 X means the subject sits below X in value, rank, or level.
低 — person radical 亻 + 氐 (base)
A semantic-phonetic compound. The left side 亻 (person) gives the meaning, while 氐 supplies the sound and originally depicted something reaching the ground or base. Together they suggest a person bowing low, which extended to the general sense of 'low' in height, position, or degree.
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.