1to open (transitive or intransitive)
2(of ships, vehicles, troops etc) to start
3to turn on; to put in operation; to operate; to run
4to boil
5to write out (a prescription, check, invoice etc)
6(directional complement) away; off
7carat (gold)
8abbr. for Kelvin, 開爾文|开尔文 (開爾文|开尔文 · Lord Kelvin 1824-1907, British physicist (William Thomson))
9abbr. for 開本|开本, book format (開本|开本 · book format based on how a full printing sheet is cut or folded (often abbreviated to 開|开 after a numeral, e.g. 16-kai and 32-kai, roughly A4 and A5 respectively))