切符
きっぷ · kippu · JLPT N5 · noun
ticket
🎫 切符 = cut + tally: a slip cut off as proof you paid
切 means cut and 符 means tally or token, so a ticket is literally a cut token. Sound hook: kippu, keep it — you keep your kippu until the exit gate, where the station takes it back.
切 — 七 (phonetic) + 刀 (knife radical)
切 is a semantic-phonetic compound: 刀 'knife' gives the meaning of cutting, while 七 supplies the sound. The original sense was to slice or cut with a blade. From there it extended figuratively to 'close to' (as in pressed against) and 'urgent/earnest', as in 切实.