Ditty and Oratorio

Ditty noun - A short musical composition for the human voice often with instrumental accompaniment.

Oratorio and ditty are semantically related In some cases you can use "Oratorio" instead a noun "Ditty".

Oratorio noun - A musical composition for voices and orchestra based on a religious text.

Ditty and oratorio are semantically related in religious song topic. You can use "Ditty" instead a noun "Oratorio".