⊕ (Unicode: U+2295) is a Symbole for:

• more ringed direct Sum in algebra (official name of the symbol unicode)
• the cross of Odin or Woden
• the planet Ground, like Synonymous with ♁
• alloy of the Copper in Alchemy
• a sphere with the equator and a Meridian
• the logical OR exclusive Operator

This relatively simple symbol (a cross in a round) is very old and was used for many significances different in the majority from civilizations.

See too