Definition of emblem from the Webster-Merriam Dictionary:
1 : a picture with a motto or set of verses intended as a moral lesson.
2 : an object or the figure of an object symbolizing and suggesting another object or an idea.
3a : a symbolic object used as a heraldic device. b : a device, symbol, or figure adopted and used as an identifying mark.
Origin: Late 16th century (as a verb): from Latin emblema ‘inlaid work, raised ornament’, from Greek emblēma ‘insertion’, from emballein ‘throw in, insert’, from em– ‘in’ + ballein ‘to throw’.