Lexical semantics is the study of word meaning. Descriptively speaking, the main topics studied within lexical semantics involve either the internal semantic structure of words, or the semantic relations that occur within the vocabulary. Within the first set, major phenomena include polysemy (in contrast with vagueness), metonymy, metaphor, and prototypicality. Within the second set, dominant topics include lexical fields, lexical relations, conceptual metaphor and metonymy, and frames. Theoretically speaking, the main theoretical approaches that have succeeded each other in the history of lexical semantics are prestructuralist historical semantics, structuralist semantics, and cognitive semantics. These theoretical frameworks differ as to whether they take a system-oriented rather than a usage-oriented approach to word-meaning research but, at the same time, in the historical development of the discipline, they have each contributed significantly to the descriptive and conceptual apparatus of lexical semantics.
There are two main theoretical traditions in semantics. One is based on realism, where meanings are described as relations between language and the world, often in terms of truth conditions. The other is cognitivistic, where meanings are identified with mental structures. This article presents some of the main ideas and theories within the cognitivist approach. A central tenet of cognitively oriented theories of meaning is that there are close connections between the meaning structures and other cognitive processes. In particular, parallels between semantics and visual processes have been studied. As a complement, the theory of embodied cognition focuses on the relation between actions and components of meaning. One of the main methods of representing cognitive meaning structures is to use images schemas and idealized cognitive models. Such schemas focus on spatial relations between various semantic elements. Images schemas are often constructed using Gestalt psychological notions, including those of trajector and landmark, corresponding to figure and ground. In this tradition, metaphors and metonymies are considered to be central meaning transforming processes. A related approach is force dynamics. Here, the semantic schemas are construed from forces and their relations rather than from spatial relations. Recent extensions involve cognitive representations of actions and events, which then form the basis for a semantics of verbs. A third approach is the theory of conceptual spaces. In this theory, meanings are represented as regions of semantic domains such as space, time, color, weight, size, and shape. For example, strong evidence exists that color words in a large variety of languages correspond to such regions. This approach has been extended to a general account of the semantics of some of the main word classes, including adjectives, verbs, and prepositions. The theory of conceptual spaces shows similarities to the older frame semantics and feature analysis, but it puts more emphasis on geometric structures. A general criticism against cognitive theories of semantics is that they only consider the meaning structures of individuals, but neglect the social aspects of semantics, that is, that meanings are shared within a community. Recent theoretical proposals counter this by suggesting that semantics should be seen as a meeting of minds, that is, communicative processes that lead to the alignment of meanings between individuals. On this approach, semantics is seen as a product of communication, constrained by the cognitive mechanisms of the individuals.