1) Semantic unit 
speech element that expresses an idea
(from the article `linguistics`) ...functional in the sense in which this term was interpreted in the pre-World War II period. The most valuable contribution made by the postwar ...
rheme 1. That part of a proposition or sentence that expresses a single idea. Specialized use in current linguistics: that part of a sentence giving new information about a theme. 2. In linguistics, the expression of a single idea or notion; a semanteme; any semantic unit or element of speech. 3. The part of a sentence, often the predicate, that ad...
A term applied to the new information conveyed in a sentence.