'Earth-like' originates from Old English 'eorðe' (earth) and Old English 'gelīc' (like), where 'eorðe' meant 'ground; soil; the planet Earth' and 'gelīc' meant 'similar'.

'Earth-like' developed from Middle English combinations such as 'erthe-lyk' or 'erthe-lich' (formation by combining the noun for earth and an adjective-forming element meaning 'like'), and over time stabilized as the modern compound/adjective 'Earth-like' (also written 'Earthlike').

Initially, formations combining 'earth' and 'like' often described things related to the ground or earthly nature; over time the compound evolved to specifically mean 'resembling the planet Earth', especially in scientific/astronomical contexts.