Open English Wordnet
Nouns
(n)message, content1, subject matter, substancecontent communicating a message; what something is about
(n)content1, cognitive content, mental objectthe sum or range of what has been perceived, discovered, or learned
(n)subject, content1, depicted objectsomething (a person or object or scene) selected by an artist or photographer for graphic representation“a moving picture of a train is more dramatic than a still picture of the same subject”
(n)contentedness, content2the state of being contented with your situation in life“he relaxed in sleepy contentedness”, “they could read to their heart's content”