- 1週期性的、定期的
If something is periodic, it happens again and again, usually with a fairly regular gap in between — a periodic check, periodic meetings, periodic rain in the afternoon. It does not have to be perfectly clock-like; the point is that it returns, rather than happening once. It is a slightly formal, textbook-ish word. In everyday talk people more often say “regular,” “every so often,” or “from time to time.” Scientists also use it for things that follow a repeating pattern (that is why the periodic table has that name: the properties come round again in a cycle). Though actually, there is a different, rarer chemistry word periodic (as in periodic acid), built another way, from per- + iodic; that is not this meaning.
From the word’s history
From French périodique, from Medieval Latin periodicus 'cyclical', from Ancient Greek περίοδος 'cycle'; period + -ic.
借自法文 périodique，源自希臘文 períodos「循環、週期」。
組成period（一段時間／一個循環）+ -ic（變成形容詞）。來自法文 périodique、中世紀拉丁文 periodicus，再往上是拉丁文 periodus、古希臘文 περίοδος（循環、一周）。
同家族的字
- perioda stretch of time or a cycle; the noun inside this sense
- periodicallythe adverb: from time to time, at intervals
- periodicala magazine that comes out at regular times
原始詞典資料8 筆記錄
以下是外部詞典記錄的用法，摘錄並精簡格式，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
periodicadj詞源 1/ˌpɪɹiˈɒdɪk/
- 1
Relative to a period or periods.
- 2
Having repeated cycles.
- There was some laughter, and Roddle was left free to expand his ideas on the periodic visits of cowboys to the town. “Mason Rickets, he had ten big punkins a-sittin' in front of his store, an' them fellers from the Upside-down-F ranch shot 'em up […].”
- 3
Occurring at regular intervals.
- That last problem did intrude on Hazzard’s roamings, and when she refers to the living city it is with periodic references to thefts of cars and wallets, with a warning not to carry anything “snatchable” by the thieves on motorcycles who whiz through the streets.
- 4
Periodical.
- 5
astronomynatural-sciencesPertaining to the revolution of a celestial object in its orbit.
- 6
mathematicssciencesFor which any return to it must occur in multiples of k time steps, for some k>1.
- 7
Having a structure characterized by periodic sentences.
periodicadj詞源 2/ˌpɜːɹaɪˈɒdɪk/
- 1
Relating to the highest oxidation state of iodine; of or derived from a periodic acid.
摘錄自 英文維基詞典 English Wiktionary，已精簡格式；依 CC BY-SA 4.0 授權使用，改動後的內容同樣以此授權提供。