The term 'reduce bit by bit' can be summarized by two crossword solutions: 'ERODE' and 'PARE'. ERODE is a verb meaning to gradually wear away or diminish, usually through the action of natural elements such as wind or water. PARE is also a verb meaning to reduce or trim away the outer layer or surface of something, usually with a knife or other sharp tool. Both words are used to describe the process of reducing something bit by bit.