per acids [obsolete]

https://doi.org/10.1351/goldbook.P04482
An ambiguous term, which may imply either a higher oxidation state of a central atom, as in perchloric acid, or a derivative of hydrogen peroxide, as in CH3C(=O)OOH. Accordingly, it is not recommended as a class name.
See: peroxy acids
Source:
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1356 (https://doi.org/10.1351/pac199567081307)