提速
tí sù · HSK 7
to speed up
🚄 提 raise + 速 speed = raise the speed; to pick up speed, speed up
提 means to lift or raise, 速 means speed or velocity. Put together, 提速 literally raises the speed — what a high-speed train does when it picks up the pace on the track.
提 — hand radical 扌 + 是 (phonetic)
提 is a semantic-phonetic compound. The hand radical 扌 gives the meaning, since the character originally referred to lifting or carrying something by hand. The right side 是 supplies the sound. From 'lift up' it extended to 'raise (an issue),' 'mention,' and 'bring forward.'