A young or female hawk or falcon, especially one taken from the nest for falconry training.
From Old French 'nis' (nest) through Middle English 'eyse' or 'nyas,' with the 'n' initially attached to the article 'une' (a nest). The word underwent metanalysis where speakers reanalyzed where word boundaries fell.
The word 'eyess' is a spectacular example of how language changes through mishearing—'a nyas' got reheard as 'an eyess,' and this reanalysis stuck around in falconry terminology for centuries, showing that mistakes can become permanent parts of language!
Complete word intelligence in one call. Free tier — 50 lookups/day.