The word "science" in European languages comes from a root which originally just means "knowledge". In English, since the 19th century, there has been a tendency to confine it to those branches of study which are grouped together as "natural sciences" (as contrasted with other subjects). Such classifications or groupings of subjects vary over time. E.g. the medieval European curriculum (apart from theology) consisted of "the seven sciences", also called "the seven liberal arts" (!). These were

the quadrivium (literally, "meeting of four ways) - the higher division
the trivium ("meeting of three ways", from which the modern word "trivial") - the lower division