The term 'Mark of Approval' refers to a sign or symbol that is used to indicate approval or acceptance. The four solutions for this term are 'TICK', 'SEAL', 'STAMP', and 'CACHET'. A 'TICK' is a small mark, usually in the shape of a cross, that is used to indicate agreement or acceptance. A 'SEAL' is a device or impression that is used to authenticate documents or other items. A 'STAMP' is an official mark or design that is used to indicate authenticity or approval. Finally, a 'CACHET' is a special mark or design that is used to indicate quality or distinction.