THOR was an agency or title held by a Starfleet officer at Starfleet Command's Fleet Operations Center, Sol Sector.
In January of 2155, Starfleet officers S. Westmore and K. White were working in or as THOR. It and the officers' name were listed on directory placards. (ENT: "Demons", directories)
THOR, like many of the other agencies or titles on the directories, was a reference to NASA and ISS terminology, in this case, the "Thermal Operations and Resources".