The words terse, terce sound the same but have different meanings and spellings. Why do terse, terce sound the same even though they are completely different words?
The answer is simple: terse, terce are homophones of the English language.
Variant of tierce.
Brief and to the point; effectively concise: a terse one-word answer.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.