The term 'Thanks a ___!' is commonly used to express gratitude for something. The crossword solutions for this term are HEAP (4 letters), LOT (3 letters), MILLION (7 letters), and MIL (3 letters). HEAP is a large amount of something, usually referring to a pile of objects. LOT is also a large amount, but it is usually used to refer to a group of people or things. MILLION is an even larger amount, usually referring to a very large number of something. Mil is short for MILLION, and is used to refer to a large number of something.