If we go by the simple fact that Science is a Method, scientific publication in its simplest form is a publication that is rooted in the method of science (observation, problem statement, hypothesis, data gathering, experiment/analysis and results etc.). Which is basically the application of empirical procedures for solving societal problems.
It's a good question because all of the branches of science lie on a continuum and blend into each other (like the wavelengths of the EM spectrum) and even cross over into subjects like philosophy and psychology!