'non-hysteretic' is formed in modern English by the negative prefix 'non-' plus 'hysteretic'. 'Hysteretic' comes from 'hysteresis', which ultimately derives from Greek 'hysterein' meaning 'to be late' or 'to lag behind'.

'hysterein' (Greek, 'to be late/lag') gave rise in New Latin/technical usage to 'hysteresis' (19th century), which entered English as 'hysteresis' meaning a lagging or dependence on past states; the adjective 'hysteretic' was formed from that noun, and later the prefix 'non-' was added to create 'non-hysteretic'.

Initially related to the idea of 'lagging behind' (physical delay), the term 'hysteresis' evolved to denote dependence on past states or history; 'non-hysteretic' therefore came to mean 'lacking such history-dependent lag' or 'not showing hysteresis'.