Associativity is a grammatical category which expresses the meaning "X and the group (of one or more members) associated with X", where X is a nominal, typically of human reference. An example is the Hungarian János-ék meaning "John and associates / John and his group / John and them", or the Japanese Tanaka-tachi meaning "Tanaka and associates / Tanaka and his group / Tanaka and them".
Associations in English can be identified by words such as with, or along with. Another name for this is Instrumental Case. Instrumental Case, in the past--has been identified as 'means by which', in that it expresses the notion of means by which an action was done.
 Associative Case., http://ccat.sas.upenn.edu/plc/tamilweb/book/chapter2/node23.html.
 Associative/Instrumental Case., http://ccat.sas.upenn.edu/plc/tamilweb/book/chapter2/node22.html.
 Instrumental Case: Means by Which., http://ccat.sas.upenn.edu/plc/tamilweb/book/chapter2/node24.html#SECTION00135200000000000000.