'task-based' originates from Modern English, specifically formed by combining the noun 'task' and the past-participle adjective 'based' (from 'base'). 'task' comes into English via Old French 'tasque' / 'taske' from Medieval Latin 'tasca', and 'base' comes from Old French 'bas' and Latin 'basis'.

'task' changed from Medieval Latin 'tasca' (meaning 'tax, duty') to Old French 'tasque'/'taske' and then to Middle English 'taske', eventually becoming modern English 'task' with the sense 'piece of work'. 'base' changed from Greek 'basis' to Latin 'basis', through Old French 'bas' and Middle English 'base', and 'based' developed as the past participle/adjectival form; the compound 'task-based' is a modern English formation combining these elements.

Initially, 'task' often referred to a duty or imposed payment ('tax, duty'); over time it shifted to mean a piece of work or assignment. 'task-based' therefore developed to mean 'having a foundation/structure in tasks', a meaning that matches modern usage.