To seal off.
To terminate; to call the end of.
To terminate a computer program.
To make trades offsetting an existing position, leaving the trader with a neutral position.
Of a wave, to break all at once, instead of progressively along its length.
To exclude by blocking all opportunities to enter or join.
Synonym of close (“to make a sale”)
To seal an opening, so as to prevent the entry of draughts.
That prevents the entry of draughts.