IPA: /ˈkaʊntərfɔɪl/
KK: /ˈkaʊntərˌfɔɪl/
A piece of paper that is kept as a record of a transaction, often attached to a check or ticket.
She kept the counterfoil of the check for her records.
Counterfoil → It is formed from "counter-" (meaning against or opposite) and "foil" (from Old French *foille*, meaning leaf or sheet). The word refers to a part of a document that is opposite to the main part, often serving as a duplicate or record.
Think of 'counter-' meaning against or opposite, and 'foil' as a sheet — together they describe a part of a document that acts as a duplicate or record.
No commonly confused words.