Accounts receivable. The people who handle payments, and who hound delinquent accounts to pay up.

We used to have all hands meetings in which everybody talked (not the CEO yakking) explaining what they were doing and what they planned to do.

Our A/R clerk explained what she did. She managed to get almost everybody to pay on time (cough not the assholes at Sun though). Her avg was something like 35 days (we wrote everything net 30 or less). The next quarter she reported that she'd gotten the average down to something like 23 days, and got a standing ovation! For a ~60 person bootstrapped company that meant a lot, and this exercise meant everybody appreciated her work.

Accounts Receivable, one assumes.

Almost certainly. Though the music industry's "Artists and Repertoire" (sometimes abbreviated AR, sometimes A&R) is a not-particularly-close second.

To make matters worse, I have seen A&R being used to mean "Accounts and Receivables", which is just WRONG (except in the context of tertiary education institutions).