The term LOOK UP can be broken down into two crossword solutions: GAIN (4 letters) and RESEARCH (8 letters). GAIN is a verb that means to acquire or obtain something, usually through effort. It can also mean to increase in size, number, or strength. RESEARCH is a noun that refers to the systematic investigation into and study of materials and sources in order to establish facts and reach new conclusions. It is often used to GAIN knowledge or understanding of a subject. Together, LOOK UP can be interpreted as an instruction to acquire knowledge or understanding by researching or studying materials and sources.