From a software development perspective, a Syntax Parser is a program that reads your code and determines what it does and if its grammer is valid. The syntax parser is part of the process of converting code into a bunch of instructions that the computer can understand and execute. So basically your code is not what is given to the computer, but rather a translation of it.
S y n t a x ::: provides rules to put together words to form components of sentence and to put together these components to form sentences.
P a r s i n g ::: is a method to perform syntactic analysis of a sentence.