What does utter mean?

An utter is to make a noise with a voice,some say its where u get milk but its not that an udder

A bovine mammary would actually be an udder. It is good you pointed out how close the two Words are.

Utter has two meanings. One is basically to say something or make a sound. The other is the most extreme point.

Examples:

I want complete silence. Do not utter a Word.

I fell flat on my butt in front of everyone. I am utterly embarrassed.