You are definitely misinformed in that area. A Terry frisk is typically a pat down of the outer clothing, and perhaps nearby containers and hiding places, in response to specific reasonable suspicion of a weapon that could cause immediate danger to a police officer or the public nearby.

Several elements are different about what the TSA does, the most obvious being the lack of any reasonable suspicion.

Additionally, the sliding motion a TSO uses is not a "pat down". It is a more intrusive hand movement. Also, a TSO will search areas that are highly unlikely to contain a weapon, such as the hair and the groin area.

Federal Law Enforcement Training Center info on Terry Frisk