The term 'Brightness Measure' can be broken down into two crossword solutions: Lumen (5 letters) and IQTest (6 letters). Lumen is a unit of measurement for the amount of light emitted from a source, while IQTest is an abbreviation for Intelligence Quotient Test, which is a standardized test used to measure intelligence. Both of these terms are related to the concept of brightness measure, as they both measure different aspects of it.