The word spur as a noun indicates a spike on the back of horseman’s boot to goad a horse into action, and for the same reason as a verb it signifies “encouraging action”. Because of this, Guillim assigns the meaning “press onward” to the prescence of a spur in a coat of arms. A Display of Heraldry, J. Guillim, Blome, London, 1679, P256 It can be depicted either as the full item, with connections to the boot, or just as the star-shaped spur rowel which contains the spikes. A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1894, Entry:Spur