Syntax refers to the actual language elements and symbols themselves. Questions should be tagged as syntax when the question specifically and almost completely relates to syntax alone. This tag should be used with a specific language tag
Definition
In computer science, the syntax of a programming language is the set of rules that define the combinations of symbols that are considered to be correctly structured programs in that language. The syntax of a language defines its surface form. Text-based programming languages are based on sequences of characters, while visual programming languages are based on the spatial layout and connections between symbols (which may be textual or graphical).
The lexical grammar of a textual language specifies how characters must be chunked into tokens. Other syntax rules specify the permissible sequences of these tokens and the process of assigning meaning to these token sequences is part of semantics.
The syntactic analysis of source code usually entails the transformation of the linear sequence of tokens into a hierarchical syntax tree (abstract syntax trees are one convenient form of syntax tree). This process is called parsing, as it is in syntactic analysis in linguistics. Tools have been written that automatically generate parsers from a specification of a language grammar written in Backus-Naur form, e.g., Yacc (yet another compiler compiler).
Source: Syntax (Programming Languages) - Wikipedia
Usage
On StackOverflow, questions should be tagged as syntax when the question specifically and almost completely relates to syntax alone. Additionally, a tag should be added corresponding to the language that is being used, as the syntax only makes sense in the context of the language. Adding the correct language tag will ensure that the question will reach an audience capable of answering it.
