除了
chúle · HSK 3
except
➖ 除 = remove/divide + 了 (particle); 'having removed X' = except X
除 means to remove or divide (the division sign ÷ is called 除号). Pair it with the aspect particle 了 and you get 除了 — literally 'having taken X out', which English renders as 'except' or 'besides'.
除 — left ear/mound 阝 + surplus 余
除 combines the 'mound/steps' radical 阝 (originally 阜, a hill) with 余 as the phonetic. It first meant the steps of a palace, then extended to 'remove' or 'clear away' (as one sweeps steps clean), and later to mathematical 'divide.'
了 — pictograph of swaddled child with no arms
了 originally depicted an infant wrapped in swaddling cloth, with the arms hidden or bound — a variant of 子 (child) without the arms. From 'finished wrapping' it extended to mean 'completed' or 'finished,' which is its main modern grammatical use as an aspect particle marking completed action.