From Longman Business Dictionary
associationas·so·ci·a·tion /əˌsəʊsiˈeɪʃən, əˌsəʊʃi-əˌsoʊ-/ written abbreviation assn noun [countableC]ORGANIZATIONS a group of people or organizations who have the same aims or do the same kind of workthe National Association of Purchasing Managers
→ housing association → industry association → staff association