join

Entry Definition
s/he unites h/, joins h/ together; (usually, with plural direct object) s/he unites them, joins them together
(two) they are joined together, they branch out from a common source
s/he joins in the chase
s/he takes part in it, belongs to it; s/he joins it (activity, etc.)
s/he takes part in it, belongs to it; s/he joins it (activity, etc.)
s/he joins in, participates, attends
s/he joins in conversation