Wiktionary
hydroxamic acid
n. (context chemistry English) any compound derived from an oxoacid by replacing the hydroxyl with -NHOH or derivatives
Wikipedia
Hydroxamic acid
A hydroxamic acid is a class of organic compounds bearing the functional group RC(O)N(OH)R', with R and R' as organic residues and CO as a carbonyl group. They are amides (RC(O)NHR') wherein the NH center has an OH substitution. They are often used as metal chelators.