'algae-susceptible' is a compound of 'algae' and 'susceptible'. 'algae' originates from Latin, specifically the word 'alga', where 'alga' meant 'seaweed'. 'susceptible' originates from Latin, specifically the adjective 'susceptibilis', from 'suscipere' meaning 'to take up' or 'receive'.

'algae' came into English from Latin 'alga' (via Medieval/Scientific Latin) and developed into the modern plural form 'algae'; 'susceptible' passed into English from Old French (susceptible) and Medieval Latin 'susceptibilis', eventually becoming English 'susceptible'. The compound 'algae-susceptible' is a modern English compound formed by combining these elements to describe susceptibility to algae.

Initially, 'alga' referred specifically to 'seaweed' and 'susceptible' meant 'capable of being affected or received'; over time the compound evolved to mean 'likely to be affected by or to support the growth of algae'.