The name "Littelfuse" originated from a creative spelling modification of its original core product category. When founder Edward V. Sundt invented the company's first small protective fuse in 1927, he attempted to trademark the phrase "Little fuse". Because the United States Patent and Trademark Office rejected the application on the grounds that the words were too common, Sundt cleverly resolved the issue by reversing the letters "l" and "e" at the end of the first word to permanently establish the brand name Littelfuse.