動詞 oscillate:

1. be undecided about something; waver between conflicting positions or courses of action
   同義詞：hover, vibrate, vacillate
2. move or swing from side to side regularly
   同義詞：vibrate

1. A pendulum oscillates.
   擺錘能擺動。
2. Manic depressives oscillate between depression and elation.
   躁狂抑郁癥患者抑郁與躁狂交替發(fā)作。
3. He oscillates between political extremes.
   他的政治觀點在兩個極端之間搖擺不定。

os.cil.late

v.intr.（不及物動詞）
os.cil.lat.ed,os.cil.lat.ing,os.cil.lates
To swing back and forth with a steady, uninterrupted rhythm.
持續(xù)周期性地擺動：以穩(wěn)定的、不間斷的節(jié)奏來回?fù)u擺
To waver, as between conflicting opinions or courses of action; vacillate:
動搖，猶豫：猶豫不決，如在不同意見或不同方案上；躊躇：
例句：
.The court has oscillated over the decades from more liberal to less, more conservative to less, depending upon who was president at the time of vacancies.(Gordon J. Humphrey)See Synonyms at swing
.幾十年來法庭一直（在自由和保守問題上）搖擺不定，自由多了就限制些，太保守了就自由點，這一切都取決于誰來填補總統(tǒng)這個空缺.(戈登J.漢弗萊)參見 swing

Physics To vary between alternate extremes, usually within a definable period of time.
【物理學(xué)】 振蕩，振動：在兩個振動極端間變化，通常指在一段確定的時間里

來源：
Latin ôscill3re ôscill3t-
拉丁語 ôscill3re ôscill3t-
from ôscillum [swing]
源自 ôscillum [擺動]
probably from ôscillum [small mask of Bacchus] [diminutive of] ôs [mouth] * see ôs-
可能源自 ôscillum [酒神巴克斯戴的小假面] [] ôs的小后綴 [嘴] *參見 ôs-

【引伸】
os.cilla.tor
n.（名詞）
os.cillato.ry
<注釋>The rather dry wordoscillate may become a bit less dry as we learn its story. It is possible that it goes back to the Latin wordôscillum, a diminutive ofôs, .mouth,. meaning .small mouth.. In a passage in theGeorgics, Virgil applies the word to a small mask of Bacchus hung from trees to move back and forth in the breeze.From this wordôscillum may have come another word ôscillum, meaning .something, such as a swing, that moves up and down or back and forth..And thisôscillum was the source of the verb ôscill3re, .to ride in a swing,. and the noun (from the verb) ôscill3tio, .the action of swinging or oscillating.. The words have given us, respectively, our verboscillate, first recorded in 72', and our noun oscillation, first recorded in '58. The next time one sees something oscillating,one might think of that small mask of Bacchus swinging from a pine tree in the Roman countryside.
當(dāng)我們了解了與oscillate 有關(guān)的傳說時，這個較為枯燥的詞就會變得不那么干巴巴的了。 此詞可被追溯到一個拉丁詞oscillum， 可簡寫成os， .嘴.，意為.小嘴.。 在農(nóng)事詩集 的一節(jié)中， 維吉爾用這個詞指掛在樹上在微風(fēng)中來回擺動的酒神巴克斯的小假面具。從oscillum 一詞可以得出另一詞 oscillum， 指.前后或上下擺動的某物，如秋千。.而這里的oscillum 便是意為.在秋千上擺動.的動詞 oscillare 和意為.擺動或搖動的動作.的名詞（從動詞來） oscillatio 的詞源。 從這些單詞中分別得出了我們今天所用的動詞oscillation （首次記錄于72'年）和名詞 oscillation （首次記錄于'58年）。 以后若看見物體在擺動，就很可能會想起古羅馬鄉(xiāng)間一棵松樹上搖來晃去的巴克斯的小假面具了