Ambiguity means confusion about what is conveyed, since the current context may lead to different interpretations of meaning. Many words in many languages have multiple definitions. Ambiguity is an effect of a rupture of the rule of identity in the context of the exchange of information. Particularly the sender may be physically absent, and the contexts explicitly divergent, such as will be the case when the receptor is a reader and the sender was a writer.
Pragmatics is the study of how context affects meaning. The two primary forms of context important to pragmatics are linguistic context and situation context.
Linguistic context is how meaning is understood without relying on intent and assumptions. In applied pragmatics, for example, meaning is formed through sensory experiences, even though sensory stimulus cannot be easily articulated in language or signs. Pragmatics, then, reveals that meaning is both something affected by and affecting the world. Meaning is something contextual with respect to language and the world, and is also something active toward other meanings and the world. Linguistic context becomes important when looking at particular linguistic problems such as that of pronouns.
Situation context refers to every non-linguistic factor that affects the meaning of a phrase. An example of situation context can be seen in the phrase "it's cold in here", which can either be a simple statement of fact or a request to turn up the heat, depending on, among other things, whether or not it is believed to be in the listener's power to affect the temperature.
Semantics is the study of how meaning is conveyed through signs and language. Understanding how facial expressions, body language, and tone affect meaning, and how words, phrases, sentences, and punctuation relate to meaning are examples. Various subgroups of semantics are studied within the fields of linguistics, logic and computing. For example, linguistic semantics includes the history of how words have been used in the past; logical semantics includes how people mean and refer in terms of likely intent and assumptions.
During the 19th century, John Stuart Mill defined semantic meaning with the words "denotation" and "connotation". A denotation is the literal or primary meaning of a word. Connotations are ideas or feelings that a word invokes for a person in addition to its literal or primary meaning.
The original use of "meaning" as understood early in the 20th century occurred through Lady Welby, after her daughter translated the term "semantics" from French.
Languages allow information to be conveyed even when the specific words used are not known by the reader or listener. People connect words with meaning and use words to refer to concepts. A person's intentions affect what is meant. Meaning (in English) as intent harkens back to the Anglo-Saxons and is associated today still, with the German verb meinen as to think or intend.
Ferdinand de Saussure in founding semiology, his original subset of the semiotics, started describing language in terms of Signs, dividing those signs in turn into signifieds and signifiers. The signifier is the perceptive side of a sign, thus the sound form in case of oral language. The signified is the signification (semantic) side, the mental construction or image associated with the sound, by either a speaker and hearer. A sign, then, is essentially a relationship between signified and signifier.
Signs are essentially conventional, as any foreign language student is well aware: there is no reason that bat couldn't mean "body of water" or even "that bust of Napoleon over there". Since the choice of signifiers is ultimately arbitrary, the meaning cannot somehow be in the signifier. Saussure instead defers meaning to the sign itself: meaning is ultimately the same thing as the sign, and meaning means that relationship is between signified and signifier. All meaning is both within us and communal, thus cultural. Signs "mean" by reference to our internal lexicon and grammar, and despite there being a matter of convention, so the communal part, signs also, because of the individual's uniqueness, can mean something only to the individual (what red means to one person may not be what red means to another, either in absolute value, or by including what's suggested by the context). However, while meanings carried by one given set of signifiers may vary to some extent from individual to individual, only those meanings that stay within a boundary are seen by other speakers of the language to belong to the language: if one were to refer to smells as red, most other speakers would assume the person is talking nonsense (although statements like this are common among people who experience synesthesia, or in poetry).