Coat of arms of Nash

The blazon

az. on a chev. betw. three ravens heads, erased, ar. a pellet, betw. four cross crosslets sa. — Crest, an arm, erect, couped at the elbow, vested az. cuffed ar. holding in the hand ppr. an acom-branch vert, fructed ppr. [Borne by William Nash, Esq. Lord Mayor of London, 1772.]

A blazon is the description of a coat of arms in the technical language of heraldry. The drawing comes from that text, and from nothing else.