My word is defined as an expression of surprise or dismay and it is the equivalent of saying "my gosh" or "my goodness."(interjection)
An example of my word is when you see ten bushels of strawberries and say "My word, that is a lot of strawberries!"
My word means a promise.(noun)
An example of "my word" is when you say "I promise to be there" which could also be said as "I give you my word I will be there."