What is a RMD in regards to office of personnel management retirement payments? My mom gets the survivor benefits. Is this an RMD?

Please see this answer from Macuser:

Just say it is all a RMD.

Virtually all pension plans, defined contribution plans, and annuities in existence today fall under section 401 of the tax code.

Required minimum distributions for defined benefit plans and annuity contracts all require RMD's after age 70 1/2 (age 72 after 2019).  If you receive periodic (monthly) payments from any pension plan you can be assured that the custodian of the plan is meeting the requirements so you can safely answer "yes" to the question.

The answer to the question does not go on your tax return, it is simply to make sure you do not owe any penalty for not taking the RMD or use it for an ineligible rollover.

The question is just to be sure that the requirement was met.