'ischemic' originates from New Latin/medical formation, specifically the word 'ischaemicus', ultimately from Greek 'ἰσχαιμία' ('ischaimia'), where the element 'isch-' meant 'to restrain/hold back' and 'haima' meant 'blood'.

'ischemic' changed from the New Latin/medical term 'ischaemicus' (via Medieval/Neo-Latin usage of Greek 'ischaimia') and eventually became the modern English adjective 'ischemic' through medical Latin and English adoption.

Initially, it denoted 'a restriction of blood (to tissues)' (i.e., reduced blood flow), but over time it evolved into the adjectival form meaning 'relating to or caused by such restriction' used in medical contexts.