"promise to obey"
vow
The definition of the word vow is a solemn promise or dedication to something.
There isn't a special meaning for each letter in the word marriage. Many believe that the term stems from the Latin language, and that it means young woman.
vow
oath
To "give your word" means to promise.
"I give you my word" means that the speaker is making a promise or commitment to do something. It implies that the person's word is trustworthy and that they will follow through with their promise.
commit, pledge
oath
Owe, IOU
Breaking a Promise