WordNet (r) 3.0 (2006):

box office
    n 1: total admission receipts for an entertainment
    2: the office where tickets of admission are sold [syn: box
       office, ticket office, ticket booth]

Moby Thesaurus II by Grady Ward, 1.0:

64 Moby Thesaurus words for "box office":
   attendance, avails, booking office, branch, branch office, cabinet,
   chambers, chancellery, chancery, closet, commissions, consulate,
   corporate headquarters, credit, credits, den, disposable income,
   dividend, dividends, draw, earned income, earnings, embassy,
   executive office, frequence, frequenting, gains, gate,
   gate receipts, get, gross, gross income, gross receipts,
   headquarters, home office, income, intake, legation, main office,
   make, net, net income, net receipts, number present, office,
   output, proceeds, produce, profits, receipt, receipts, receivables,
   returns, revenue, royalties, shop, study, take, take-in, takings,
   ticket office, turnout, unearned income, yield