Today's Word of the Day means...
A part of every sentence. The subject tells what the sentence is about; it contains the main noun or noun phrase: “The car crashed into the railing”; “Judy and two of her friends were elected to the National Honor Society.” In some cases the subject is implied: you is the implied subject in “Get me some orange juice.” (Compare predicate.)
In subject-oriented programming, a subject is a collection of classes or class fragments whose class hierarchy models its domain in its own, subjective way. A subject may be a complete application in itself, or it may be an incomplete fragment that must be composed with other subjects to produce a complete application. Subject composition combines class hierarchies to produce new subjects that incorporate functionality from existing subjects.