Synonyms for Tc (same or very similar meaning)
WordNet sense 1 (a crystalline metallic element not found in nature; occurs as one of the fission products of uranium):
technetiumWordNet sense 2 (a permanent council of the United Nations that commissions a country (or countries) to undertake the administration of a territory):
Trusteeship CouncilFrom the ODE community, based on WordNetadd/edit