At the signal is a phrase that is used to indicate when an action should be taken. The term can be broken down into three parts: CUE (3 letters), bell (4 letters), and oncue (5 letters). CUE is a prompt or indication that an action should be taken, such as a word or gesture. Bell is a sound made by a device, usually a metal instrument, that is used to signal an event or action. Oncue is an adverb that means at the exact time or moment that is expected or required. Together, these three words form the phrase 'at the signal, ' which is used to indicate when an action should be taken.