The superclass of all classes describing products or services types, either by nature or purpose. Examples for such subclasses are "TV set", "vacuum cleaner", etc. An instance of this class can be either an actual product or service (gr:Individual), a placeholder instance for unknown instances of a mass-produced commodity (gr:SomeItems), or a model / prototype specification (gr:ProductOrServiceModel). When in doubt, use gr:SomeItems.
Examples:
a) MyCellphone123, i.e. my personal, tangible cell phone (gr:Individual)
b) Siemens1234, i.e. the Siemens cell phone make and model 1234 (gr:ProductOrServiceModel)
c) dummyCellPhone123 as a placeholder for actual instances of a certain kind of cell phones (gr:SomeItems)
Note: Your first choice for specializations of gr:ProductOrService should be http://www.productontology.org.
Compatibility with schema.org: This class is (approximately) equivalent to http://schema.org/Product.