"An unmarried daughter bears her father's arms on a lozenge-shaped shield, without any addition or alteration."
Berry, Encycl. Herald. 1830:—
"The arms of maidens and widows should be borne in shields of this shape."
Robson, British Herald, 1830:—
"Lozenge, a four-cornered figure, differing from the fusil, being shorter and broader. Plutarch says that in Megara [read Megura], an ancient town of Greece, the tombstones under which the bodies of Amazons lay were of that form: some conjecture this to be the cause why ladies have their arms on lozenges."
Porny, Elements of Heraldry, 1795, supposes—
"The lozenge may have been originally a fusil, or fusée, as the French call it: it is a figure longer than the lozenge, and signifies a spindle, which is a woman's instrument."
This writer also quotes Sylvester de Petra Sancta, who would have this shield to "represent a cushion, whereon women used to sit and spin, or do other housewifery."
Brydson, Summary View of Heraldry, 1795:—
"The shields on which armorial bearings are represented are of various forms, as round, oval, or somewhat resembling a heart; which last is the most common form. Excepting sovereigns, women unmarried, or widows, bear their arms on a lozenge shield, which is of a square form, so placed as to have one of its angles upwards, and is supposed to resemble a distoff."