melody

Compared meaning: a tune or melody (noun).

比较义项：曲调，旋律（名词）。

• air

  A literary or old-fashioned word for a tune, mostly found in music or poetry today; rarely used in everyday conversation.

  一种文学化或较为陈旧的说法，指曲调，如今主要出现在音乐或诗歌语境中，日常口语中很少使用。

  The old fiddler played a haunting air passed down through generations.

  那位老提琴手演奏了一首代代相传、扣人心弦的曲子。

• tune

  The everyday, most common word for a simple musical sequence; used casually in speech, e.g. humming, whistling, or 'catchy tune'.

  日常生活中最常用的词，指简单的乐曲；用于口语中，例如哼唱、吹口哨，或『朗朗上口的曲调』。

  I can't get that catchy tune out of my head today.

  我今天满脑子都是那首朗朗上口的曲子，怎么也甩不掉。

• melody 本词

  A more musical or literary word, often for the main, memorable line of a piece of music; suggests beauty or artistry.

  更具音乐性或文学色彩的词，常指乐曲中主要、令人难忘的旋律线，带有优美、富有艺术感的意味。

  The composer wrote a beautiful melody for the film's opening scene.

  这位作曲家为电影的开场画面创作了一段优美的旋律。

Air, tune, and melody can all mean the tune of a piece of music. Tune is the most common and casual word. Melody is more artistic or literary, often describing a beautiful, memorable musical line. Air is old-fashioned and literary, rare in daily conversation.

这三个词在此义项上都指乐曲的曲调或旋律，但语域和使用频率不同：tune 最口语化、最常用；melody 更具艺术性，常形容优美动听的旋律；air 是较陈旧、文学化的说法，日常很少使用。这里不比较 air 的『神态，样子』这一义项。