megachain

mega- +‎ chain

megachain (plural megachains)

1. A very large and successful chain (group of stores or businesses).
   • 2007 January 3, Julie Bosman, “A Princeton Maverick Succumbs to a Cultural Shift”, in New York Times‎:

     Independent bookstores, of course, have been under siege for nearly two decades by the megachains and the Web retailers, and have been steadily dropping away, one by one.

• chain

• genmaicha