Semantics is variously defined, according to R. Schuldt as:
- The relationships of characters or groups of characters to their meanings, independent of the manner of their interpretation and use. Contrast with syntax.
- The science of describing what words mean, the opposite of syntax
- The meanings assigned to symbols and sets of symbols in a language.
- The study of meaning in language, including the relationship between language, thought, and behavior.
- The meaning of a string in some language, as opposed to syntax which describes how symbols may be combined independent of their meaning.
See syntactic/semantic/pragmatic for more rigourous terms.
 distinctions required
Any semantics requires some arbitrary distinction choices to be made if only to categorize every item, usually resulting in fixed categories and taxonomy to relate those. These however have POV, and are contextual and fragile, as Clay Shirky for instance emphasizes in What time does to categories (invited talk to LongNow) in which he also advocates weak ontology or folksonomy and avoiding any power-based attempt to categorize.
 ontological vs. ordinary vs. operational
- A very strong one at the borders of the ontology that permits only a weak ontology to apply between the new type and the existing ones - an ontological distinction that defines a given concept as being in one or another
- An ordinary distinction arising in or from praxis and observed patterns, as made in semiotics or human sciences, or work functions like sysopping and provisioning, and appearing typically in instructional capital that one skilled in the art is expected to be able to understand
- An operational distinction that has an actual repeatable objective test to disjunct one type from another, as in natural sciences, industrial engineering (including open systems) and systems integration (including open configuration), which deal in utterly interchangeable parts such as atoms, molecules like DNA, PCI-E cards, USB devices, etc. See green telecom for a major source of operational distinctions in this wiki.
 heart of best practice
Most of best practice involves more careful semantical distinction as one evolves and new problems emerge - continuous improvement of the distinctions one makes in ordinary practice. See five levels of intranet for the changes that one can anticipate in an organization trying to govern reflectively using more careful semantical distinctions.
The way in which the distinctions themselves are expressed is not very important except insofar as it enables interoperability and integrativity (see below).
 semantics versus syntax
A syntactical distinction is a much lower order concern and helps determine which semantical distinctions apply - which type or identity is being claimed or asserted. For example, between we, trolls and wheat rolls there is only a syntactical distinction. See ambiguate for practical guidance on this and obscure/conflate/confuse for a strategy to resist abuses of this method.
 what's all this about a semantic web?
Supposedly, a semantic web relies on semantic not syntactical distinctions.
While a naively semantic web relies on authority to make final decisions on causality and similarity, a sociosemantic web arises from many choices about these made by users - folksonomy - clashing and being reconciled into a common taxonomy via new troll point of view. A main goal of public wikis is to socialize taxonomy so it becomes standard and spreads, increasing the awareness of the key distinctions. See categorize pages for practical guidance on this.
 semantic interoperability
Efforts toward semantic interoperability increase the shared meaning of a string of characters and/or symbols in some language within a context that assures the correct interpretation by all actors. Some efforts of this nature include EIA-836, XBRL, ACORD and (minor) PLCS, OAGIS, HL7.
A subtly different concept, integrativity, refers to the inherent tendency of a particular item to converge or diverge in definition as one examines more cases. Some concepts like where/when/who, have high integrativity and tend to converge to better definitions on examination, resulting in geospatial, time and person/credential standards. Other concepts like what or why tend to diverge due to point of view, Simpson's Paradox and framing differences. All living ontology patterns have an inherent degree of integrativity that is assessed based on their underlying verb pairs. The ii process increases integrativity by social means, i.e. socialize taxonomy, so that discourse occurs in the terms that are more rather than less integratable.
 improving issue integrativity
Because advocates of different action/position/solutions bias any debate to favour the terms of reference which preposition towards what they advocate, issues have low integrativity and therefore require very deliberate effort to discover issue statements that mediate effectively between all known positions. See issue/position/argument on how this is accomplished, openpolitics.ca and openingpolitics.org for good examples of this done.
The more contentious and controversial the issue, the more difficult the problem of improving integrativity. The worst such problems tend to be global and social, with complex ecological and infrastructural implications that prevent simple assessments of solutions. See resilience economics for more on the semantical distinctions that apply in urgent or emergency contexts.