To seal an opening, so as to prevent the entry of draughts.
That prevents the entry of draughts.
To seal or fasten with a wafer.
A thin disk of consecrated unleavened bread used in communion.
A light, thin, flat biscuit/cookie.
A soft disk originally made of flour, and later of gelatin or a similar substance, used to seal letters, attach papers etc.
A thin disk of silicon or other semiconductor on which an electronic circuit is produced.