An Academy of Sciences is a national academy or another learned society dedicated to sciences.
In non-English speaking countries, the range of academic fields of the members of a national Academy of Science often includes fields which would not normally be classed as "science" in English. Many languages use a broad term for systematized learning which includes both natural and social sciences and fields such as literary studies, history, art history etc. which are not typically labelled "sciences" in English. This can be illustrated by contrasting examples from the English speaking world and the non-English speaking world. The Australian Academy of Sciences is an organization of natural scientists, reflecting the English use of the term "scientist." There are separate academies for Arts, Humanities and Social Science. The Hungarian "Academy of Science" (Magyar Tudományos Akadémia) however, has members drawn from many other areas of academia, including those not considered science in English. What has presumably happened is that the Hungarian term "tudómány" has been translated as "science" - in a broad sense as it was used in English 200 years ago, and is still used in French and other languages.
As the engineering sciences have become more varied and advanced, there is a recent trend in many advanced countries to organize the national Academy of Engineering (or Engineering Sciences), separate from the national Academy of Sciences.