hem in (someone/something)

to surround someone or something.

They found themselves hemmed in by the crowd.

The building was hemmed in by high walls.

• on a slippery slope
• on a tangent
• on automatic pilot
• on a wing and a prayer
• on back
• on balance
• on behalf of
• on behalf of someone
• on bended knee
• on bended knees
• on best behavior
• on blocks
• on board
• on borrowed time
• on call
• on case
• once again
• once and for all
• Once bitten, twice shy.
• once in a blue moon
• once-in-a-lifetime
• once in a lifetime
• once in a while
• once upon a time
• on cloud nine