All 6 meanings

1. (transitive) to open (to make something accessible or allow for passage by moving from a shut position)
2. (transitive) to open (to make accessible to customers or clients)
3. (transitive, computing) to open (to load into memory for viewing or editing)
4. (intransitive) to open, get, or answer the door
5. (reflexive) to open (to become open)
6. (reflexive) to open up (to), confide (in) (to reveal oneself; share personal information about oneself)