Is my 401(k), 403(b), or TSP considered an IRA?

No. 401(k), 403(b), and Thrift Savings Plans (TSPs) aren't the same thing as an IRA.

When we ask if you have a traditional or Roth IRA, don't answer Yes if you have a 401(k), 403(b), or TSP—unless you have an IRA in addition to any of these.