'dragonfly' originates from English, a compound of 'dragon' and 'fly'. 'Dragon' ultimately comes from Latin and Greek ('draco'/'drakon'), and 'fly' comes from Old English 'flēoge' meaning a flying insect.

'dragonfly' appears in Early Modern English (16th century) as the compound 'dragon-fly' and developed into the single word 'dragonfly' in later usage, influenced by the element 'dragon' (from Old English 'draca' and Latin 'draco').

Initially named for a fanciful association with 'dragon' (perhaps because of appearance or perceived ferocity), it has long been used to denote the insect and retained that primary sense into modern English.