In general, a concept is a semantic entity. It is a specific kind of meaning. Consequently, the expression semantic concept would seem to be pleonastic. However, inside linguistics, it may designate a particular kind of concept, in the following sense:

The object of linguistics, viz. language, is a heterogeneous agglomeration of different kinds of entities. Among them are phonological, grammatical, semantic and pragmatic entities. Concepts may then be classified according to the kind of entity they comprise. By this criterion, there are phonological, grammatical, semantic and pragmatic concepts (and yet others).

The intension of a grammatical concept is composed of semantic and structural features. Since these two kinds of features belong to entire distinct realms of the language system, grammatical concepts have been dubbed “hybrid”. For instance, the concept of a preposition embodies the structural features of being a word that governs a nominal complement and preceding this complement. It embodies the semantic features of specifying some relation that its complement bears to a component of the context. These two kinds of criteria are partly independent of each other. There are other kinds of words that govern a nominal complement, for instance verbs. And there are other kinds of entities that specify a relation of their complement to a component of the context, for instance case markers and conjunctions. A grammatical concept specifies a means of linguistic structure which fulfills a function of linguistic semantics.

The intension of a semantic concept is composed exclusively of semantic features. It is, in the sense relevant here, not hybrid, but homogeneous, viz. purely semantic. If lexical meanings are concerned, the features can, in principle, be just any kind of features; and to this extent, a semantic concept in linguistics would not differ decisively from an everyday notion like ‘cup’ or ‘abdicate’. In the present context, however, semantic concepts contrast with grammatical concepts. Only such semantic concepts are of interest here which may be coupled with a grammatical concept. More precisely, these are such semantic concepts whose component features may also be part of grammatical concepts. These are, in general, features from the realms of communication and cognition. A subset of concepts of the areas of communication and cognition are commonly paired with means of grammatical structure. They are sometimes called ‘functional concepts’ since communication and cognition are the two principal functions of human language. It is specifically these semantic concepts that are often hard to distinguish from grammatical concepts.

Why is it necessary to distinguish semantic from grammatical concepts? There are many pairs of a semantic and a grammatical concept, like sex vs. gender, time vs. tense etc. Since the association of meaning and expression in language signs is a many-to-many relation, the members of such a pair are never synonymous.

1. Semantic concepts are variable:
   • A semantic concept is commonly prototypical in nature. For instance, a goal is normally a place; but nothing prevents conceiving a human being as a goal of some movement.
   • A semantic concept may be a feature of different grammatical concepts and, thus, be coded in different forms. For instance, the goal relation may be coded by an allative case, an allative preposition or a directional verb affix.
2. Grammatical concepts are variable:
   • At the typological level, a grammatical concept is prototypical both as regards its structural and as regards its semantic basis. For instance, an allative is by default a case; but a preposition of the same function would also be called allative. And while motion or transport towards a goal is its semantic basis, an allative case which also codes the benefactive relation can still be an allative case.
   • At the language-specific level, a grammatical concept is nailed down on the particular structural means coding it. For instance, the dative case of a language may cover various semantic functions like the allative or the benefactive, but still be the dative case of the language. However, if the semantic features constituting this concept reappear in another item, be it the benefactive case or some valency operator on a verb, these could not possibly be subsumed under the dative case of the language.

Confusion of these two categories of linguistic concepts is pervasive in the literature of the discipline. Here are some pairs of semantic and grammatical concept to illustrate the difference: