I've been trained to use the word ground and the ground symbol to refer to the earth, the dirt on which we stand.
Circuit common is considered to be a separate concept, with the symbol .
My understanding is that "ground" means that the node can and should be tied to the earth. "Common" implies an arbitrary voltage reference with no connotation about its voltage relative to earth. One might have multiple commons in a schematic, but earth is earth.
Obviously there are cases where "ground" is used to mean what I defined above as "common". Would those cases be wrong? Does my use of terminology match standard usage?