The terms grammar and punctuation are often used interchangeably. While we use both grammar and punctuation to clearly explicate our ideas for our readers, they are not the same.
Punctuation marks are the symbols we use to clarify meaning, question marks, exclamation points, periods, etc.
Grammar is the structure of language. You can think of it as word order and choice. How we order our language is part of what determines meaning.
While grammar and punctuation are very complex topics, I have simplified the meanings here for one main reason, to remind us that differentiating between grammar and punctuation when we grade student writing will help students better be able to correct their mistakes the next time. When we simply say, “work on your grammar and punctuation,” it all gets grouped together in the student’s mind, and it makes it difficult for students to ask for specific help when they come to tutoring. It is not necessary to point out every grammar error on student papers. However, writing something such as “This paper has many subject verb agreement issues,” and then highlighting one or two examples within the paper can really help students learn to be better writers.
One More Thought. . .
It can also help to further define grammar by discussing descriptive and prescriptive grammar. Descriptive grammar is how we use language every day, with all of its dialects and cultural differences. Prescriptive grammar is a list of rules that define how grammar is used in certain settings (i.e. school). When students are writing for school, they are learning to negotiate between the expectations of a school and professional language and what may seem culturally or historically accurate (what comes naturally).
For further thinking. . . See Michael Swan’s “What is Grammar?”