曲 and 歌詞: listening, performing, writing, and checking meaning
Compare 曲 as a song that recalls home or a piece performed at a concert with 歌詞 as lyrics written for a mood or checked for meaning. Track the object and action without adding composition, singing, or a return home.
曲: a song heard or a piece performed
曲 (きょく) refers to a song or musical piece. 「この曲を聞くと故郷を思い出す。」 means “This song reminds me of my hometown.” Listening to this song brings the hometown to mind. Recalling home is not the same as physically returning there; no trip home is stated.
「演奏会の最後に短い曲を弾いた。」 means “We performed a short piece at the end of the concert.” A short piece was performed at the end of the concert. The action is performing the piece, rather than composing it. The sentence does not identify who wrote the music.
歌詞: words written or investigated
歌詞 (かし) refers to lyrics. 「曲の雰囲気に合う歌詞を自分で書いた。」 means “I wrote lyrics to suit the mood of the song.” What the speaker wrote was the lyrics, chosen to suit the song's mood. Writing those words does not itself establish that the speaker composed the melody or performed the song.
「知らない言葉があったので歌詞の意味を調べた。」 means “There was a word I did not know, so I looked up the meaning of the lyrics.” An unfamiliar word prompted the meaning lookup. Keep that reason without assuming that every word in the lyrics was unknown or that the speaker sang the song after checking the meaning.
Match each object to its stated action
曲 and 歌詞 are related musical objects, but the actions in these examples differ. The first song example links listening with remembering home, while the concert example describes playing a piece. How music was encountered and what the listener remembered should remain distinct.
For the lyrics, one example concerns writing words to fit a mood and the other concerns looking up meaning because of an unfamiliar word. These separate sentences do not establish one person's complete sequence of lyric writing, composition, and performance. Read each action within the information its sentence provides.
In 「曲の雰囲気に合う歌詞を自分で書いた。」, did the speaker write the song's melody?
Show the answer and why
The stated object is the lyrics, written to fit the song's mood. The sentence does not say that the speaker composed the melody or completed a performance. 歌詞 keeps the focus on the song's words.