Is there a terminology for this?

One obvious result of the fact that words do not have meanings as people have heads is that different people may have different meanings for the same word and different words for the same meaning.  These differences may be individual or they may be associated with a particular group, class, or region.  Individual differences come from differing  individual experiences.  They often lie in the area of connotation, that is, the body of emotional associations which a person has with a word.  The total meaning of such a word as brother for any given person will depend on such matters as whether or not he had a brother or brothers, and if he did what his relations with his brothers were like.  From this point of view it can be said that no two persons -- except, perhaps, identical twins -- have the same meanings for any word.  That's why reactions to poetry, which often depends rather heavily on connotation, differ greatly from one reader to another.