| Theodor Morell | Theodor Morell |
| Theodor Reuss | Theodor Reuss |
| Theodor Schwann | Theodor Schwann |
| Theodor Svedberg | Theodor Svedberg |
| Theodor von Redding | Teodoro Reding |
| Theodor von Reding | Teodoro Reding |
| Theodora | Teodora |
| Theodore | Teodoro |
| Theodore Beza | Teodoro de Beza |
| Theodore Dreiser | Theodore Dreiser |
| Theodore Harold Maiman | Theodore Harold Maiman |
| Theodore I Laskaris | Teodoro I Láscaris |
| Theodore II | Teodoro II |
| Theodore II Laskaris | Teodoro II Láscaris |
| Theodore Kaczynski | Theodore Kaczynski |
| Theodore Prodromus | Teodoro Pródromo |
| Theodore Roosevelt | Theodore Roosevelt |
| Theodore Schultz | Theodore Schultz |
| Theodore Simon | Theodore Simon |
| Theodore Sturgeon | Theodore Sturgeon |
| Theodore William Richards | Theodore Richards |
| Theodoric I | Teodorico I |
| Theodoric II | Teodorico II |
| Theodoric of Prague | Maestro Theodoric |
| Theodoric the Great | Teodorico el Grande |
| Theodoros Deligiannis | Theodoros Deligiannis |
| Theodoros Kolokotronis | Theodoros Kolokotronis |
| Theodoros Pangalos | Theodoros Pangalos |
| Theodoros Papaloukas | Theodoros Papaloukas |
| Theodosia | Teodosia |
| Theodosian dynasty | Dinastía Teodosiana |
| Theodosios III | Teodosio III |
| Theodosius | Teodosio |
| Theodosius Dobzhansky | Theodosius Dobzhansky |
| Theodosius I | Teodosio I el Grande |
| Theodosius II | Teodosio II |
| Theodric of Bernicia | Teodric de Bernicia |
| Theofanis Gekas | Theofanis Gekas |
| Theognis | Teognis |
| Theognis of Megara | Teognis |
| theologian | teólogo |
| theological | teológico |
| Theological anthropology | Antropología de la religión |
| Theological virtues | Virtudes teologales |
| theology | teología |
| Theology of the Body | Teología del Cuerpo |
| Theon of Alexandria | Teón de Alejandría |
| Theopaschism | Teopasquismo |
| Theophano | Teófano Anastaso |
| Theophanu | Teófano Skleraina |
| theophany | teofanía |
| Theophilos | Teófilo |
| Theophilus | Teófilo |
| Theophrastaceae | Theophrastaceae |
| Theophrastus | Teofrasto |
| Theora | Theora |
| theorbo | tiorba |
| theorem | conjetura |
| Theorem of Pythagoras | Teorema de Pitágoras |
| theoretic | teórico |
| theoretical | académico |
| Theoretical astrophysics | Astrofísica teórica |
| Theoretical biology | Biología teórica |
| Theoretical chemistry | Química teórica |
| Theoretical computer science | Teoría de la computación |
| theoretically | teóricamente |
| Theorie | Teoría |
| theorist | teórico |
| theorize | teorizar |
| theory | teoría |
| theory of chances | teoría de probabilidades |
| Theory of cognition | Gnoseología |
| theory of combinations | teoría de combinaciones |
| Theory of computation | Teoría de la computación |
| Theory of Constraints | Teoría de las limitaciones |
| theory of equations | teoría de ecuaciones |
| theory of evolution | teoría de evolución |
| Theory of forms | Mundo de las ideas |
| theory of gravitation | teoría de gravedad |
| Theory of Human Sciences | Teoría de las Ciencias Humanas |
| Theory of literature | Teoría |
| Theory of mind | Teoría de la mente |
| Theory of multiple intelligences | Teoría de las inteligencias múltiples |
| theory of probability | teoría de probabilidades |
| theory of relativity | teoría de relatividad |
| Theory of special relativity | Teoría de la Relatividad Especial |
| theosophic | teosófico |
| Theosophical Society | Sociedad Teosófica |
| theosophist | teósofo |
| theosophy | teosofía |
| Theotokos | Theotokos |
| Theramenes | Terámenes |
| therapeutic | terapéutico |
| Therapeutic horseback riding | Equinoterapia |
| Therapeutic touch | Toque terapéutico |
| therapeutics | terapéutica |
| therapist | terapeuta |
| Therapsida | Therapsida |
| therapy | terapia |
| Theravada | Theravāda |
| there | allí |
| there are | hay |
| there be | haber |
| there is | hay |
| there is an exception to every rule | no hay regla sin excepción |
| There Is Nothing Left to Lose | There is Nothing Left to Lose |
| there is nothing new under the sun | no hay nada nuevo bajo el sol |
| there's | hay |
| there's been an accident | ha habido un accidente |
| there's many a slip twixt cup and lip | de la mano a la boca desaparece la sopa |
| there's no accounting for taste | para gustos hay colores |
| there's no fool like an old fool | la cabeza blanca y el seso por venir |
| there's no place like home | mi casa y mi hogar cien doblas val |
| thereabout | aproximadamente |
| thereabouts | aproximadamente |
| thereafter | después |
| thereby | por lo tanto |
| therefore | luego |
| therein | en eso |
| thereinafter | despues |
| thereof | de eso |
| Theres | Teres I |
| Theresa of Avila | La Abulense |
| Therese Neumann | Teresa Neumann |
| thereto | a eso |
| thereupon | luego |
| Theria | Theria |
| Theriodont | Theriodontia |
| Theriodontia | Theriodontia |
| Therizinosaur | Therizinosauroidea |
| Therizinosaurus | Therizinosaurus |
| Thermaic Gulf | Golfo de Tesalónica |
| thermal | termal |
| Thermal camera | Cámara térmica |
| Thermal Design Power | Thermal Design Power |
| Thermal element | Termopar |
| Thermal energy storage | Almacenamiento de calor |
| thermal equipment | equipo térmico |
| Thermal history | Historia térmica |
| Thermal imaging device | Cámara infrarroja |
| thermal power plant | central térmica |
| Thermal property | Propiedad térmica |
| Thermal structure | Estructura térmica |
| Thermal transfer | Transferencia de calor |
| Thermal treatment | Tratamiento térmico |
| Thermal wind | Viento térmico |
| Thermaltake | Thermaltake |
| thermic | térmico |
| thermionic | caluroso |
| thermionic tube | lámpara termoiónica |
| thermistor | termistor |
| thermite | termita |
| Thermite welding | Soldadura aluminotérmica |
| thermo- | termo- |
| Thermo-couple | Termopar |
| Thermo-luminescence | Termoluminiscencia |
| Thermobaric weapon | Bomba termobárica |
