Wax formerly melted onto a letter to seal it; the picture of the sender's seal was often pressed into the wax as evidence that the letter had not been opened.
A soft disk originally made of flour, and later of gelatin or a similar substance, used to seal letters, attach papers etc.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 consecrated unleavened bread used in communion.
A light, thin, flat biscuit/cookie.
A thin disk of silicon or other semiconductor on which an electronic circuit is produced.
To seal or fasten with a wafer.