One way to hold this word: a weight hanging on a long string. Let it go and it swings to one side, then back to the other, then back again. Each swing takes about the same time and covers about the same ground. It is not travelling anywhere — it stays in one place and keeps crossing between two sides. Everything else the word does is that same weight with something else hung in its place: a price, a mood, or an electric current.
From the word’s history
The word was taken into English in the 1720s from Latin ōscillō, meaning to swing, which comes from ōscillum, a swing. So the swinging picture is not a teaching invention — it sits in the word's own history.
這個字大約在一七二〇年代進入英文，來自拉丁文 ōscillō「擺盪」，而 ōscillō 又來自 ōscillum「一個鞦韆」。所以「來回擺盪」這個畫面不是後來想出來的比喻，它本來就在這個字的來歷裡。
Wiktionary 'oscillate' (packet evidence, source_ref kaikki:3f6f69a190036ae4:825976018:15825)
登入就可以看每一支怎麼連回核心畫面。