The crossword solution for the term 'Widen, as a hole opening' is REAM. Reaming is a process used to enlarge and smooth a hole in a material. It is typically done with a reamer, which is a type of cutting tool that has multiple blades or flutes. The reamer is inserted into the hole and rotated, cutting away material until the desired size is achieved. Reaming is often used in machining and manufacturing processes to ensure precise and accurate hole sizes.