To lock up or secure something firmly; to enclose or confine with or as if with locks.
From 'be-' (to cause to be or make) plus 'lock' (Old English 'loc,' a fastening device). Medieval verb formation creating the sense of 'to make locked' or 'to lock up completely.'
Belock is an archaic verb that shows how English once had more flexibility—instead of saying 'lock up,' people could say 'belock,' and this pattern survives in words like 'befriend.'
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