'equal-awned' is a modern English compound formed from 'equal' + 'awn'. 'equal' originates from Latin, specifically the word 'aequalis', where 'aequus' meant 'even' or 'level'. 'awn' originates from Old English, originally denoting a bristle or beard-like appendage on grasses.

'equal-awned' developed in modern botanical English by combining 'equal' (which entered English via Old French and Middle English from Latin 'aequalis') and 'awn' (an Old English word for a bristle on grasses); the compound itself is a descriptive modern formation rather than a single inherited lexical item.

Initially, the elements meant 'even/level' (equal) and 'bristle/beard-like appendage' (awn); combined in botanical usage they now mean 'having awns of equal length' as a single descriptive adjective.