See Azure, an annulet argent, p. 48.
"The Manual of Heraldry; Fifth Edition" by Anonymous
Annulet: a small or narrow ring or annulus.
"Explanation of Terms Used in Entomology" by John. B. Smith
Dymoke, each lyon charged sur l' espale with an Dymoke annulet .
"A History of Horncastle from the earliest period to the present time" by James Conway Walter
Cole of Cornwall bears, inter alia, a =bordure sable=, charged alternately with =bezants= and annulets.
"The Curiosities of Heraldry" by Mark Antony Lower