The Collaborative International Dictionary of English v.0.48:

Provider \Pro*vid"er\, n.
   One who provides, furnishes, or supplies; one who procures
   what is wanted.
   [1913 Webster]

WordNet (r) 3.0 (2006):

provider
    n 1: someone whose business is to supply a particular service or
         commodity [syn: supplier, provider]
    2: someone who provides the means for subsistence

Moby Thesaurus II by Grady Ward, 1.0:

20 Moby Thesaurus words for "provider":
   caterer, chandler, commissariat, commissary, donor, furnisher,
   manciple, merchant, patron, provisioner, purveyor, quartermaster,
   retailer, steward, stock clerk, storekeeper, supplier, sutler,
   victualer, vivandier



The Free On-line Dictionary of Computing (30 December 2018):

Internet Access Provider
IAP
provider

    (IAP) A company or other origanisation
   which provides access to the Internet to businesses and/or
   consumers.  An IAP purchases an Internet link from another
   company that has a direct link to the Internet and resells
   portions of that bandwidth to the general public.

   For example, an IAP may purchase a T1 link (1.544Mb/s) and
   resell that bandwidth in chunks consisting of ISDN (64Kb/s,
   128Kb/s) and analog modems (14.4Kb/s, 28.8Kb/s).  The IAP's
   customer base is likely to include both businesses and
   individuals.  Individual customers usually connect to the IAP
   via a modem and telephone line to a (preferably local) point
   of presence.

   An IAP may also be an Internet Service Provider.

   (1996-06-25)