Final answer:
The amount of compensation being withheld to buy an annuity under a 403(b) plan is called contribution.
Step-by-step explanation:
The amount of compensation being withheld to buy an annuity under a 403(b) plan is called contribution. In a 403(b) plan, both the employer and the employee contribute a fixed amount to the worker's retirement account on a regular basis. This contribution is then used to purchase an annuity, which is a financial product that provides regular income during retirement.