At least here in the USA confusion arises over what I separate (and so do House and Harman) into "morphology" the way words change and effect each other, and "syntax" (the way sentences are put together). It is because of this that I hate to hear someone refer to the "simple predicate" of a sentence as the "verb" of the sentence. "Grammar" I use to cover both studies, and, of course "linguistics", the science of language, is way broader, including semantics, phonetics, writing systems, usage, dialect geography, etc.