Of businesses selling to other businesses.

business matters shouldn't be influenced by friendship or sentiment

(countable) A specific commercial enterprise or establishment. / (countable) A person's occupation, work, or trade. / (uncountable) Commercial, industrial, or professional activity.

Of, to, pertaining to or utilized for purposes of conducting trade, commerce, governance, advocacy or other professional purposes. / Professional, businesslike, having concern for good business practice.

plural of business

Engaged in business activity / (idiomatic) Ready to proceed in a desired activity.

Business aside from the main business. / Something secondary or subordinate.

(Los Angeles) Hollywood, the entertainment industry. / (slang) prostitution

plural of by-business

Used other than figuratively or idiomatically: see in, the, business, of. / (idiomatic) dealing heavily in or intimately involved with (a practice, behavior, etc.)