rebate

(noun) a refund of some fraction of the amount paid. Synonyms: discount.

(noun) a rectangular groove made to hold two pieces together. Synonyms: rabbet.

(verb) give a reduction in the price during a sale. Example: "The store is rebating refrigerators this week."

(verb) cut a rebate in (timber or stone).

(verb) join with a rebate. Example: "Rebate the pieces of timber and stone."