A chemical species that behaves both as an acid and as a base is called amphoteric. This property depends upon the medium in which the species is investigated:
H2SO4 is an acid when studied in water, but becomes amphoteric in superacids.
Source:
PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1083 (https://doi.org/10.1351/pac199466051077)