A doxology is a short hymn of praises to God in various forms of Christian worship, often added to the end of canticles, psalms, and hymns. The tradition derives from a similar practice in the Jewish synagogue, where some version of the Kaddish serves to terminate each section of the service.
The Eucharistic Doxology in a stained glass window of St. James' in Glenbeigh
A hymn is a type of song, and partially synonymous with devotional song, specifically written for the purpose of adoration or prayer, and typically addressed to a deity or deities, or to a prominent figure or personification. The word hymn derives from Greek ὕμνος (hymnos), which means "a song of praise". A writer of hymns is known as a hymnist. The singing or composition of hymns is called hymnody. Collections of hymns are known as hymnals or hymn books. Hymns may or may not include instrumental accompaniment. Polyhymnia is the Greco/Roman goddess of hymns.
Arvid Liljelund [de; fi; sv]'s Man Singing Hymn (1884)
In Christianity, church congregations often sing hymns together as part of their worship (Pictured: worshippers at Uffington Parish Church in England, 1944)
Hymns are often accompanied by organ music
Sanskrit manuscript page from the "Vivaha sukta" Rigveda, dated 1500–1200 BCE