defined benefit plan
(35) The term “defined benefit plan” means a pension plan other than an individual account plan; except that a pension plan which is not an individual account plan and which provides a benefit derived from employer contributions which is based partly on the balance of the separate account of a participant— (A) for the purposes of section 1052 of this title , shall be treated as an individual account plan, and (B) for the purposes of paragraph (23) of this section and section 1054 of this title , shall be treated as an individual account plan to the extent benefits are based upon the separate account of a participant and as a defined benefit plan with respect to the remaining portion of benefits under the plan.