I expect it is, but one wouldn't call other professionals, such as doctors and lawyers, academics unless they worked in academia, so why teachers? Schools are not academia, they are schools. I suppose the main purpose is education in both cases, but I hardly think primary and secondary school education counts as academic. Some aspects of the later part of secondary, yes, but not most of it.
Some teachers are very academic, but I've never thought it a proper description for most.