1. In grammar, to divide a sentence, etc. into grammatical parts and to identify those parts and their relations to each other or to state the parts of speech in a sentence.
2. To study or to analyze something by looking at its parts closely: "The reporters tried to parse the economic data to see why the market was going down."
3. to analyze computer input in a specific language against the formal grammar of that language, both to validate the input and to create an internal representation of it for use in subsequent processing.