X marks the spot is an idiom that may be confusing. An idiom is a word, group of words or phrase that has a figurative meaning that is not easily deduced from its literal definition. We will examine the meaning of the expression X marks the spot, where it came from and some examples of its use in sentences.
X marks the spot is a phrase that means this is the exact location, the thing that you are looking for may be found in this exact area. The earliest known use of the term X marks the spot occurred in 1813, though it is safe to assume that the term was in use before this time. The idea of X designating an area holding something one is seeking stems from the concept of treasure maps. Most scholars do not believe that pirates and others truly used treasure maps. Treasure maps with an X marking the spot are mostly stuff of literary invention or are used by criminals in fraudulent schemes. The term X marks the spot has attained a wider use, to state one is in an exact location, or that one may find what he is looking for in an exact area. Note that the X in X marks the spot is properly rendered as an uppercase letter.
Examples
The sole actor, Anjanette Hall as The Pilot (we never learn her real name), is placed by production designer Tesia Dugan Benson on an “X marks the spot” space delineated by intersecting jet runways. (Cleveland Scene Magazine)
And X marks the spot: The first team to reach the end gets first dibs on digging up the buried treasure chest full of prizes worth $7,500, plus a free trip to Panama for the whole team complete with luxury villas, scuba diving and more. (Honolulu Magazine)