Hidden treasure is a term used to describe a valuable item or collection of items that have been hidden away and forgotten. The term can refer to anything from buried pirate treasure to a forgotten family heirloom. The crossword solutions for the term 'hidden treasure' are TROVE, HOARD, and STASH. TROVE refers to a large collection of valuable items, HOARD is a verb meaning to accumulate and store up, and STASH is a noun referring to a secret hiding place.