What word to use instead of another?

Answer 1

I think you mean something like "What is the word for a word that we can use instead of another word, because it has nearly the same meaning, for example, suppose I want another word for 'dog', and I speak of a 'canine', or I want another word for 'shout' and I say 'yell'".

The word for such a word is "synonym". We say that "yell" is a synonym for "shout" and of course, "shout" is a synonym for "yell".