The term 'BLUEPRINT DATUM' is a combination of two words that refer to a specific type of engineering drawing. The word 'BLUEPRINT' refers to a type of paper-based reproduction of an engineering drawing, while the word 'DATUM' refers to a reference point or line used in engineering drawings. The crossword solutions for this term are SPEC (4 letters) and AREA (4 letters). SPEC stands for Specification, which is a document that outlines the requirements for a particular product or service. AREA stands for AREA of Interest, which is a specific AREA of a drawing that is being focused on.