Pronunciation of English ⟨th⟩
In English, the digraph ⟨th⟩ usually represents either the voiced dental fricative phoneme /ð/ (as in this) or the voiceless dental fricative phoneme /θ/ (as in think). Occasionally, it stands for /t/ (as in Thailand, or Thomas).
Source: Wikipedia — Pronunciation of English ⟨th⟩ (CC BY-SA 4.0)