What is a cash check?

A check that is not crossed and marked 'Not Negotiable' may be taken into a bank (for example) and exchanged for it's value in cash 'across the counter'.

A check that has been crossed and is marked 'Not Negotiable' (this can be either pre-printed by the issuing financial institution onto a book of otherwise 'blank' (no information or value) checks, or hand-written by the issuer) may only be paid into the payee's bank account. The proceeds of such a check will only be available to the payee via his/her bank account once the check has 'cleared' (i.e. the bank has verified that there are sufficient funds available in the account of the 'issuer' to cover the value of the check and then the value is transferred into the account of the payee).

Via this distinction, it is possible for a check issuer to 'build in' a degree of security into a 'Non Negotiable' check compared with a 'cash' check.