A title given to serjeants at law, who are called “serjeants of the coif,” from the coif they wear on their heads. The use of this coif at first was to cover the clerical tonsure , many of the practising serjeants being clergyman who had abandoned their profession. It was a thin linen cover, gathered together in the form of a skull or helmet; tile material being afterwards changed into white silk, and the form eventually iuto the black patch at the top of the forensic wig, which is now the distinguishing mark of the degree of Serjeant at law. (Cowell; Foss, Judg.; 3 Steph. Comm. 272, note.) Brown.
Black’s Law Online Dictionary
