The term 'OPEN, AS A KNOT' can be solved by two crossword solutions: UNDO (4 letters) and UNTIE (5 letters). Both terms refer to the act of releasing a knot or tie, which is often used to secure objects together. The term 'UNDO' is often used in computing, where it refers to the action of reversing a command or operation. The term 'UNTIE' is more commonly used in everyday language to refer to the act of releasing a knot.