to include (something) in a package or envelope, esp along with something else
We have enclosed a cheque in settlement
to contain or confine (something)
to shut close in or surround (something) completely
We enclosed the field with a high fence
esp in former times, to fence off (common land) for private use
[Middle English enclosen from early French enclos, past part. of enclore to enclose, from Latin includere: see include]