在常用詞dialogue，diameter中有個(gè)希臘語源的前綴dia-， 它原是個(gè)希臘介詞，意思相當(dāng)于through或across。dia-是個(gè)原生詞綴，它只和希臘詞根結(jié)合，構(gòu)成原生詞。di-是dia-的異體， 它只用在o，u等元音字母前面。

下面先介紹幾個(gè)以dia-開頭的原生派生詞。 

diameter [ dia- = through 穿；meter =measure 測量=>“a measure through the centre 穿過中心的測量長度”→]n. line passing from one side to the other through the centre of a circle 直徑 / The diameter of the earth is about 8,000 miles. 地球的直徑約為 8,000英里。 

diametral a. 直徑的

dialogue [ dia- = across 交叉；logue = speech 說話=> “a speech across or between two persons 兩人交叉的說話”→]n. conversation 對話 / Two actors had a dialogue in the middle of the stage.兩個(gè)演員正在舞臺正當(dāng)中對話。

diagnosis [ dia- = through 通過;gnosis = inquiry 查詢=>“a decision through inquiry 通過查詢做出的決定”→] n. the discovery of the nature of disease by examining the symptoms 診斷 / The doctor made the diagnosis by using X rays and blood samples. 醫(yī)生利用X光透視與驗(yàn)血做出了診斷。

diagnostic a. 診斷的 

diagnostian n. 診斷專家