parergon n. a secondary, derivative, unnecessary, or supplemental occupation, ornament, or (creative) work. Also adj., attrib. Editorial Note: Plural parerga. (source: Double-Tongued Dictionary)
Further reading
An anadrome is a word that forms a whole new word when you spell it backwards. For example, the word “stressed” spelled backwards is “desserts.” Some people’s first names are anadromes. There’s the girl named Noel...
Twice a day the River Thames recedes, revealing a muddy shoreline. Hobbyists known as mudlarks stroll the surface searching for objects that have found their way into the river over the centuries, everything from ancient Roman jewelry to modern...