Definify.com
Webster 1913 Edition
Gules
Gules
(gūlz)
, Noun.
 [OE. 
goules
, F. gueules
, the same word as gueule 
throat, OF. gole
, goule
, L. gula
. So named from the red color of the throat. See Gullet
, and cf. Gula
.] (Her.) 
The tincture red, indicated in seals and engraved figures of escutcheons by parallel vertical lines. Hence, used poetically for a red color or that which is red. 
His sev’n-fold targe a field of 
In which two swords he bore; his word,
“Divide and reign.”
gules 
did stainIn which two swords he bore; his word,
“Divide and reign.”
P. Fletcher. 
Follow thy drum;
With man's blood paint the ground;
With man's blood paint the ground;
gules
, gules
. Shakespeare
Let's march to rest and set in 
gules
, like suns. Beau. & Fl.
Webster 1828 Edition
Gules
GULES
,Noun.