Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
section [ˈsɛkʃən] n (part) часть*f (of population, company) се́ктор; (in shop) се́кция; (of document, book) разде́л; (cross-section) сече́ние, разре́з
vt рассека́ть (рассе́чь*perf)
the business, etc section (PRESS) разде́л би́знеса, etc
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.