copulan. 系詞、介體、接合部(舌)聯桁、交配學術名詞介體：魚類、細菌免疫學、獸醫學聯桁【即基舌軟骨】：比較解剖學聯結：音樂關聯結構：統計學系詞：數學聯桁：動物學基舌軟骨：動物學聯合部：醫學英文釋義an equating verb (such as ‘be’ or ‘become’) that links the subject with the complement of a sentence