misnomer

1. N-COUNT If you say that a word or name is a misnomer, you mean that it describes something incorrectly. 誤稱; 用詞不當[usu 'a' N in sing]

Herbal "tea" is something of a misnomer because these drinks contain no tea at all. 花草“茶”是個誤稱，因為這類飲料里根本不含茶。