As nouns the difference between vendor and retail
is that
vendor is a person or a company that vends or sells while
retail is the sale of goods directly to the consumer; encompassing the storefronts, mail-order, websites, etc, and the corporate mechanisms, branding, advertising, etc that support them, which are involved in the business of selling and point-of-sale marketing retail goods to the public.
As an adjective retail is
of, or relating to the (actual or figurative) sale of goods or services directly to individuals.
As an adverb retail is
direct to consumers, in retail quantities, or at retail prices.
As a verb retail is
to sell at retail, or in small quantities directly to customers.