跨
kuà · HSK 6
to step across; to stride over
🦵 foot (足) + exaggerate (夸) = take an exaggerated wide step, straddling
When your foot makes an exaggerated motion, you end up straddling something. The sound kuà echoes 夸 (kuā, to boast), as if your legs are boasting how wide they can stretch.
跨 — foot 足 + 夸 (kuā, phonetic)
A semantic-phonetic compound. The foot radical 足 gives the meaning, since 跨 originally described stepping over or straddling something with the legs. The right side 夸 supplies the sound. The meaning later extended to 'span' or 'across,' as in crossing regions or eras.