Popper claims that falsifiability is a criterion of science (but not of meaningfulness). Scanning the original 1935 text (Logik der Forschung) it seems to me that he just refers to "Wissenschaft". Does he actually mean what English calls "Science" or the broader German sense in which the humanities and social sciences are "Geisteswissenschaften" and what we call Sciences (without a modifier) are "Naturwissenschaften"? In the English version (Logic of Scientific Discovery, 1955 or so) Popper just refers to "Science". In the German original he very occasionally does mention specifically Naturwissenschaften and sometimes modifies "wissenschaftlich" e.g. "empirisch-wissenschaftlich", but it is not clear to me whether he thinks of the demarcation criterion as applicable to all kinds of science or only to natural science.
PS I described the question as semantics of the criterion - but actually I see that it is really about the semantics of the objects to which the criterion is to be applied.