letter caseOur editors are putting together more complete content — check back in about 20 minutesletter caseletter case — noun名詞1. a written message sent to someone1.名詞釋義a written message sent to someone例句She wrote a letter to her grandmother.2. a symbol used in writing, like A, B, C2.名詞釋義a symbol used in writing, like A, B, C例句The word 'cat' has three letters.