名詞 copula:

1. an equating verb (such as `be' or `become') that links the subject with the complement of a sentence
   同義詞：copulative, linking verb

cop.u.la

n.（名詞）
Grammar A verb, such as a form ofbe or seem, that identifies the predicate of a sentence with the subject. Also called linking verb
【語法】 系詞：將一個句子的謂語和主語連起來的動詞，如be 或 seem 的一種形式 也作 linking verb
Logic The word or set of words that serves as a link between the subject and predicate of a proposition.
【邏輯學(xué)】 聯(lián)項：在一個命題的主項和謂項間起聯(lián)系作用的詞或詞組

來源：
Latin côpula [link]
拉丁語 côpula [聯(lián)系]

【引伸】
cop.ular