At my company we use the term "new logos" in context of acquiring new customers, but I never heard it before so I googled and I could barely find anything except for this one article: The Reason You’re Not Winning More New Logos
EDIT: Thanks for the explanations. I just wanted to add that in my company this term is used in very derived way, as in "we have a chance to logo here" or "we must prioritise, the client is a logo".