聲音折返回來
這一族就是核心畫面本身：實際的聲波撞到硬表面後折返，包括「那個回來的聲音」（名詞）和「聲音會折返」這件事（動詞），以及空間本身被折返的聲音填滿的狀態。
a repeated sound (echo) · noun · C2
A sound that you hear again after a loud noise, because it was made near a wall, a hill, or another hard surface.
回聲
核心畫面
One way to picture it: a sound hits a hard surface and comes back to you — the same sound arriving a second time, a little later and a little weaker. Everything else the word does is that returning-again shape, moved from sound to words to ideas to events.
你在山谷裡喊一聲，聲音撞到對面的岩壁又折回來——同樣的聲音，晚了一拍，弱了一點，再次到你耳朵裡。重點不是「發出聲音」…更多收起
你在山谷裡喊一聲，聲音撞到對面的岩壁又折回來——同樣的聲音，晚了一拍，弱了一點，再次到你耳朵裡。重點不是「發出聲音」，而是「已經發生過的東西又回來一次」。這個「折返、重現」的畫面一路延伸出去：從真的聲音，到別人的話、別人的想法，甚至到很久以前的事在今天再出現一次。From the word’s history
English echo comes, via Latin echo, from Ancient Greek ēkhṓ — related to ēkhḗ 'sound, noise'. The Greek word was also the name of the nymph Echo, who in myth could only repeat the last words others spoke: the name and the sound-word sit on the same root.
echo 經拉丁文 ēchō 來自古希臘文 ἠχώ (ēkhṓ)，與希臘文 ἠχή (ēkhḗ)「聲響」同源。希臘神話裡的山林女神 Ēkhṓ 也是這個字：她被罰只能重複別人剛說完的最後幾個字。所以這個字從一開始就同時帶著「聲音」和「只能重複別人的話」兩層，正好對上今天 echo 從回聲延伸到覆述、呼應的用法。
Wiktionary etymology tree supplied in the payload (PIE *sweh₂gʰ- > Ancient Greek ἠχή / ἠχώ > Latin ēchō > Middle English), plus the Greek proper name Ἠχώ 'sound'.
Three branches
話語與想法的折返
聲音折返的畫面直接搬到語言上：山壁把你的聲音送回來，人也可以把別人的話送回來。差別是山壁沒有選擇，而人是有意識地讓那些話再出現一次。
repeat someone's words · verb · C2
To say again the same words that someone else has just said.
覆述
事物之間的重現
最抽象的一層：折返的既不是聲音也不是話，而是「某個已經發生過的東西的影子」。它不是複製品，只是像得讓你想起前一次——就像回聲不等於原音，只是原音的殘影。
something similar to a past event · noun · C2
Something that is very similar to something that has happened or been said before.
迴響
原始詞典資料32 筆記錄
以下是外部詞典記錄的用法，原文照列，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。
Echoname/ˈɛkoʊ/
- 1
human-sciencesmysticismmythologyAn oread, punished by Hera by losing her own voice and only being able to mimic that of others.
- 2
A number of places in the United States:
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A number of places in the United States:
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A number of places in the United States:
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A number of places in the United States:
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A number of places in the United States:
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A number of places in the United States:
- 8
A number of places in the United States:
另外 4 個記錄的用法
- 9
A number of places in the United States:
- 10
A number of places in the United States:
- Experts say the smallest towns are especially vulnerable. And few places in Utah are as tiny or dry as Echo, a jumble of homes squeezed between a freight railroad and stunning red-rock cliffs. Echo was already struggling to hang on after the two cafes closed down. Then its spring-fed water supply hit critical lows this summer.
- 11
A number of places in the United States:
- 12
astronomynatural-sciences60 Echo, a main belt asteroid.
echonoun/ˈɛk.əʊ/
- 1
A reflected sound that is heard again by its initial observer.
- The babbling echo mocks the hounds.
- To you I mourn; nor to the Deaf I ſing, / The Woods ſhall anſwer, and their Echo ring.
- 2
An utterance repeating what has just been said.
- 3
communicationsjournalismliteratureA device in verse in which a line ends with a word which recalls the sound of the last word of the preceding line.
- 4
Sympathetic recognition; response; answer.
- Fame is the echo of actions, resounding them.
- Many kind, and sincere speeches found an echo in his heart.
- 5
Something that reflects or hearkens back to an earlier thing.
- The frustration with the political process that in the '60s led to the formation of resistance groups finds an echo in today's increasingly confrontational tactics.
- 6
An insignificant indirect result; a ripple.
- 7
computingengineeringmathematicsThe displaying on the command line of the command that has just been executed.
- 8
computingengineeringmathematicsAn individual discussion forum using the echomail system.
- When someone asks an off-topic question […] they are usually quickly told to knock it off. You can't ask a question about modems in an echo devoted to local-area networks.
另外 3 個記錄的用法
- 9
bridgegamesA signal, played in the same manner as a trump signal, made by a player who holds four or more trumps (or, as played by some, exactly three trumps) and whose partner has led trumps or signalled for trumps.
- 10
bridgegamesA signal showing the number held of a plain suit when a high card in that suit is led by one's partner.
- 11
An antisemitic punctuation symbol or marking, ((( ))), placed around a name or phrase to indicate the person is Jewish or the entity is controlled by Jewish people; or repurposed or reclaimed to proudly declare one's Jewishness or solidarity with Jews.
echoverb/ˈɛk.əʊ/
- 1
Of a sound or sound waves: to reflect off a surface and return; to reverberate or resound.
- With each clap of thunder echoing from one high building to another the noise was terrific.
- 2
Of a rumour, opinion, etc.: to spread or reverberate.
- The sense that it takes outrageous fortune to get inoculated echoes here in the Bay Area, where pharmacies have canceled flu-shot clinics, doctors turn away pleading patients and health officials are reduced to telling panicked callers that they should practice good personal hygiene.
- 3
To reflect back (a sound).
- Those peals are echoed by the Trojan throng.
- The wondrous sound / Is echoed on forever.
- 4
To repeat (another’s speech, opinion, etc.).
- Sid echoed his father’s point of view.
- ‘I want nothing.’ ‘Nor I,’ echoed Sydney.
- 5
computingengineeringmathematicsTo repeat its input as input to some other device or system.
- The device that is to echo the characters should be optioned for echoplexing.
- 6
bridgegamesTo give the echo signal, informing one's partner about cards one holds.
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。