What is the linguistic term for the phenomenon where Thai words share the same spelling but differ in tone and meaning?

• A Polysemy
• B Homophony
• C Synonymy
• D Homographs with tonal contrast ✓

Thai has numerous homographs where words with the same consonant and vowel spelling have different meanings distinguished only by tone (e.g., /khaa/ meaning stuck, value, kill or trade depending on tone).