| third party | tercera persona |
| third person | tercera persona |
| Third Punic War | Tercera Guerra Púnica |
| Third Reich | tercer Reich |
| Third Republic | Tercera República Francesa |
| Third Rome | Nueva Roma |
| Third Servile War | Tercera Guerra Servil |
| third stomach | tercer estómago |
| Third Temple | Tercer templo de Jerusalén |
| third time's a charm | a la tercera va la vencida |
| Third Way | Tercera Vía |
| Third World | Tercer Mundo |
| third-class | de tercera categoría |
| third-degree | de tercer grado |
| Third-generation programming language | Lenguaje de Tercera Generación |
| Third-party developer | Third-party |
| third-rate | de poca calidad |
| Third-rate film | Brassica rapa |
| Third-worldism | Tercermundismo |
| thirdly | en tercer lugar |
| thirds | terciar |
| thirst | sed |
| thirsty | sediento |
| thirteen | trece |
| Thirteen Colonies | Trece Colonias |
| Thirteen Days | Trece días |
| Thirteen desserts | Trece postres |
| Thirteen Senses | Thirteen senses |
| thirteenth | decimotercero |
| Thirteenth Council of Toledo | XIII Concilio de Toledo |
| Thirteenth dynasty of Egypt | Dinastía XIII de Egipto |
| thirtieth | trigésimo |
| Thirtieth dynasty of Egypt | Dinastía XXX de Egipto |
| thirty | treinta |
| Thirty Tyrants | Treinta Tiranos |
| Thirty Years' War | Guerra de los Treinta Años |
| thirty-eight | treinta y ocho |
| thirty-fifth | trigésimo quinto |
| thirty-five | treinta y cinco |
| thirty-four | treinta y cuatro |
| thirty-nine | treinta y nueve |
| thirty-one | treinta y uno |
| thirty-seven | treinta y siete |
| thirty-six | treinta y seis |
| thirty-three | treinta y tres |
| Thirty-Three Orientals | Treinta y Tres Orientales |
| thirty-two | treinta y dos |
| this | aquí |
