갈아요 · 갈았어요 · 갈 거예요 · 가세요 (ㄹ drops)
to replace, to change; to grind, to sharpen
Example
형광등이 나가서 새것으로 갈았어요.
The fluorescent light burned out, so I replaced it with a new one.
Word parts
Homonyms: 갈다 means 'replace', 'grind', and also 'plow' — context tells them apart.
Good to know
갈 거예요 and 가세요 look like forms of 가다 'to go', so rely on context.
Related words