noun
A song or poem of mourning, typically performed at funerals or memorial services. The term is somewhat formal and literary.
葬儀で葬送歌が流れた。
A dirge was played at the funeral.
彼は友人のために葬送歌を作曲した。
He composed an elegy for his friend.
レクイエム is a loanword from Latin, often used for a musical setting of the Catholic requiem mass, while 葬送歌 is a native Japanese term for any funeral song.
Compound of 葬送 (funeral, burial) and 歌 (song). The exact historical derivation is uncertain, but the kanji straightforwardly indicate a song for sending off the dead.