'megacontinent' originates from a combination of the Greek-derived prefix 'mega-' (from Greek 'megas', meaning 'great') and the word 'continent' (from Latin 'continēre' via Old French 'continent'), where 'mega-' meant 'great' and 'continēre' meant 'to hold together or contain'.

'megacontinent' was formed in modern English by compounding 'mega-' with the existing English word 'continent'; 'continent' itself entered English from Old French 'continent', from Latin 'continēns'/'continēre', and eventually became the modern English 'continent'.

Initially the elements meant 'great' + 'continent' (i.e., a very large continent); over time the compound has come to be used specifically to denote a 'supercontinent' or extremely large landmass in geological and general usage.