A cognizance was the totality of all the signs by which a knight could be recognized:  his arms, his crest, his pennon, his horse’s trappings, his servant’s badges.  In some cases it is used as a description of the symbol which is common to all the accoutrements, for instance, the Bear and Staff of the English Earls of Warwick. Puttenham (89) equates the cognizance with the device. ‘Devices, a terme which includes in his generality all those other, viz liveries, cognizances, emblemes, enseignes and impreses….the use and intent is but one …and that is to insuniat [insinuate] some secret wittie morall and brave purpose, either to recreate his eye, or please his phantasie, or examine his judgement or occupie his braine.’ 

See also: Arms, Blasons, Cimiers, Devices, Insegni, Liveries