Propinquity

Propinquity is a noun meaning nearness in place or time or relationship; kinship; similarity in nature.  In social psychology, propinquity is one of the main factors leading to interpersonal attraction. It refers to the physical or psychological proximity between people. Propinquity can mean physical proximity, a kinship between people, or a similarity in nature between things ("like-attracts-like"). Two people living on the same floor of a building, for example, have a higher propinquity than those living on different floors, just as two people with similar political beliefs possess a higher propinquity than those whose beliefs strongly differ. 

So those who have a mutual interest in words and their meanings have a higher propinquity than exists between those who are interested and those who are not.