tranche

A slice, section or portion.

(insurance) A distinct subdivision of a single policyholder's benefits, typically relating to separate premium increments.

(pensions) A pension scheme's or scheme member's benefits relating to distinct accrual periods with different rules.

(finance) One of a set of classes or risk maturities that compose a multiple-class security, such as a CMO or REMIC; a class of bonds. Collateralized mortgage obligations are structured with several tranches of bonds that have various maturities.