What is ebony and Ivory?

Ebony and ivory refer to two contrasting types of wood, traditionally used in piano keys: ebony is a dense, dark hardwood, while ivory is a creamy, white material often sourced from elephant tusks. The phrase is also famously associated with the song "Ebony and Ivory" by Paul McCartney and Stevie Wonder, which symbolizes harmony and unity despite differences. In a broader context, it can represent the interplay of opposites or diversity coexisting peacefully.