TSSU Views 7 meanings found TSSU is used for a government test‑signal switching unit, a union representing teaching support staff, a traffic‑systems services entity, and hospital theatre sterile services or supplies units. Medical Theatre Sterile Supplies Unit Miscellaneous TRANSMISSION SUBSTATION SERVICE – UNMETERED True Sandwich Salad Unit Traffic Systems Services Unit Community Teaching Support Staff Union Theatre Sterile Services Unit Governmental Test Signal Switching Unit