'algae-prone' is a modern compound of 'algae' + 'prone'. 'algae' ultimately originates from Latin, specifically the Medieval Latin word 'alga' meaning 'seaweed', and 'prone' comes from Latin 'prōnus' meaning 'bent forward'.

'algae' passed from Latin 'alga' into Medieval Latin and then into Modern English as 'algae'; 'prone' entered English via Latin 'prōnus' (through Old French/Middle English) and developed the sense 'likely to' in later English. The compound 'algae-prone' is a modern English formation used in technical and everyday contexts.

Initially, 'prone' literally meant 'bent forward', but over time it came to mean 'likely to' or 'susceptible to'. Combined with 'algae', the compound now means 'likely to develop algae'.