'anisoleucocytosis' originates from Greek elements: 'anisos' meaning 'unequal', 'leukos' meaning 'white', and 'kytos' meaning 'cell', plus the suffix '-osis' indicating a 'condition'.

'anisoleucocytosis' is a New Latin/modern medical formation combining Greek components ('aniso-' + 'leuco-' + 'cytosis') and emerged in medical literature as a descriptive pathological term in the late 19th to early 20th century.

Initially the component parts literally conveyed 'unequal white cell condition'; over time the term has been used specifically to denote variation in leukocyte size observed microscopically.