In heraldry, a device consisting of an eagle with outspread wings but without beak or feet, as in the arms of Montmorency. ... Found on http://www.encyclo.co.uk/local/20688
Al·le'ri·on noun [ French alérion , Late Latin alario a sort of eagle; of uncertain origin.] (Her.) Am eagle without beak or feet, with expanded wings. Burke. Found on http://www.encyclo.co.uk/webster/A/57