Syncategorematic: Property of terms: A term is syncategorematic iff it has no meaning when standing by itself, as contrasted with a categorematic term: A term that has meaning when standing by itself.
A typical example of a categorematic term is "elephant"; a typical example of a syncategorematic term is "of" as in "father of John" or "and" as in "It rains and it is cold".
Note that the point of "has no meaning when standing by itself" is not that a syncategorematic term is meaningless in the sense of not expressing any idea, but that it does not, by itself, mean a thing like a noun does: What "and" means in "It is cold and it rains" is not that there is an and to be met somewhere between the cold and the rain, but that the two statement "and" joins together are both true. Again, what "of" means in "James is the father of John" is not that there is an of roaming about in the gloaming, somewhat to the left of John, but that James is related to John by the relation of fatherhood.
The logical terms are normally taken as syncategorematic terms.