Black Widow House is a house of study for girls at the Assassins' Guild School. The Housemistress in canon is Emmanuelle-Marie Lapoignard les Deux-Epées . Following her retirement from the position owing to an attack of pregnancy, the mantle passed to Mlle Antoinette de Badin-Boucher. Girls from this house are referred to as Darners, on the grounds trhey're likely to grow up into damn fine Seamstresses.</p>
There is reference in the Discworld canon to each house of study having its own bespoke badge, but this is not elaborated upon. I have filled in a blank with a possible candidate for House Emblem. In the best traditions of Discworld heraldry, this is:- Une toile de l'araignée argent, on a field sable, with araignée Veuve Noire sable esquisée argent, charge sablier rouge. (A spiderweb silver on a black background, bearing a spider of the Black Widow type, in black but outlined silver, bearing a red hourglass). This is of course the classic and deadly venomous Black Widow spider, which carries a red marking symbolic of Death's hourglass on its back.
The Housemistress of this all-girls House is Madame Emmanuelle-Marie Lapoignard les Deux-Epées (a marginally canonical character) who teaches Swords, Bladed Weapons, and Metalwork. The motto is Latatian and is half of an aphorism, reading "...deadlier than the male." I'm sure you can fill in the blanks.