The term INVENTOR'S SPARK is composed of two crossword solutions: IDEA (4 letters). An inventor's spark is the initial IDEA or concept that an inventor has for a new invention. It is the first step in the creative process of inventing something new. This spark of inspiration can come from a variety of sources, such as a problem that needs to be solved, a new technology, or a combination of existing ideas. The spark is the starting point for the inventor to develop and refine their IDEA into a working prototype.