Fetching details from the dictionary...

to open; to undo; to unseal; to unpack
to bloom; to unfold; to spread out
to open (for business, e.g. in the morning)
to be wide (gap, etc.); to widen
to hold (meeting, party, etc.); to give; to open
to found (nation, dynasty, sect, etc.); to open (a new business); to set up; to establish; to start
to open (ports, borders, etc.)
to open (an account)
to open up (new land, path, etc.); to clear; to develop
to open (a file, etc.)
to cut open (fish)
to flare (e.g. skirt)
to slacken (into a poor posture)
to extend
to extract (root); to reduce (equation)
to change (kanji into hiragana)
窓をひらいて風を入れよう。
Let's open the window and let the air in.
花が開くのを待っている。
I'm waiting for the flowers to bloom.
本をひらいたら懐かしい写真が出てきた。
When I opened the book, a nostalgic photo came out.