Synonyms for Affiliate:

n.

blue-chip, agency, big business, anchor, base, account, acquisition, the biz, agent. fellow, copartner, colleague, cohort, partner. conjoin, bind, combine. affiliate (noun)
consort, associate, assort.
organization that is associated with another (noun)
partner, associate, branch.
subsidiary (noun)
branch, member.

v.

associate or be associated with a larger organization (verb)
relate, annex, join, confederate, connect, ally, amalgamate, unite, combine.
co-operate (verb)
intermesh, overlap, dovetail, intertwine, associate, pool, interplay, mesh, reciprocate, interlace, trade, share, participate, unite, concur, interweave, collaborate, band, confederate, co-operate, collude.
join (verb)
merge, consolidate, connect, annex, splice, adhere, couple, ally, juxtapose, wed, marry, relate, bond, affix, join, abut, attach, amalgamate, cling.
relate (verb)
correlate, pertain.
social (verb)
consort, associate, assort.

Other synonyms:

blue-chip, agency, the biz, branch, anchor, member, big business, subsidiary, copartner, acquisition. conjoin, partner. combine, colleague, cohort, base. account, bind. fellow. division. Other relevant words:
cohort, anchor, consort, division, partner, conjoin, member, combine, subsidiary, fellow, copartner, agency, bind, assort, acquisition, branch, colleague.