希臘語源的原生前綴peri-來自希臘介副詞peri，意思相當(dāng)于英語around，about (周圍）或near (附近）。它一般與希臘詞根相綴合，構(gòu)成相應(yīng)的名詞，其中很多是科技術(shù)語。

下面我們只介紹幾個常用的詞。

period [ peri- = around 周圍；od = a going 走=>“a going around 走了一圈”→]n. ① a complete and repeated length of time 周期 / A month, from new moon to new moon, is a period.從新月到下次新月的一段時間，就是一個周期。②length or portion of time 時期；期間；時代 / We lived in London for a period of time.我們在倫敦住了一段時期。

periodic a. 周期的；定期的

periodical a. 定期的，期刊的  n. 期刊， 雜志

perigee [ peri- = near 近；ge = earth 地球；-e=>“ near the earth 靠近地球”→]n. the point closest to the earth in the orbit of its satellite 近地點 / The speed is greatest at perigee, when the moon is nearest to the earth. 近地點的速度最大，此時月亮最靠近地球。

perigean a. 近地點的

perimeter [ peri- = around 周; meter = measure 尺寸=>“ the measure around some area 某地周圍的尺寸 ”→]n. the outer boundary of a figure or area 周圍線，周長 / The perimeter of a circle is more than three times its diameter. 圓的周長是直徑的3倍多。