Why are women referred to as the “distaff” side of a family?

In medieval times the marriage bargain held men responsible for the
physical labour outside of the home, while the women provided nour-
ishment and comfort inside. A distaff was a rod used to hold wool dur-
ing weaving and became a symbol of honour and respect to the value
of a woman’s work toward the family’s well-being. The equal to the
female “distaff-side” is the male “spear-side.”