Programming syntax refers to the set of rules that dictate how programs written in a particular programming language should be structured. It defines the correct combination of symbols, keywords, and other elements that make up valid statements and expressions in that language.

Syntax is crucial in coding because it ensures that the instructions given to a computer are in a format it can understand and execute. Just like human languages have grammatical rules to convey meaning, programming languages have syntax rules to convey logical instructions to a computer. A small mistake in syntax can lead to errors or unexpected behavior in the program. Therefore, adhering to the correct syntax is essential for writing code that is both understandable to humans and executable by computers.