1) Philosophical concept 
Sortal is a concept that has been used by some philosophers in discussing issues of identity, persistence and change. The simplest property of a sortal is that it can be counted, i.e. can take numbers as modifiers. For example, `pea` is a sortal in the sentence `I want two peas`, whereas `water` is not a sortal in the sentence `I want water...
• (a.) Pertaining to a sort.
Sort'al adjective Pertaining to a sort. [ Obsolete] Locke.