Definition & Meaning of "say the word ~noun"

What is the origin of the idiom "say the word" and when to use it?

The idiom "say the word" traces its origin to the concept of verbal commands and their immediate impact. The phrase highlights the anticipation and eagerness of the person addressed, poised and ready to act upon receiving the designated word or directive. It is often used to express a strong desire to help someone or to emphasize one's availability and eagerness to act on their behalf.