a piece forming or attached to the side of something
sidepiece in American English
(ˈsaidˌpis)
noun
a piece forming a side or a part of a side, or fixed by the side, of something
Word origin
[1795–1805; side1 + piece]This word is first recorded in the period 1795–1805. Other words that entered Englishat around the same time include: crunch, kingpin, mirage, oxidize, sharpshooter