Pakiṇṇaka 28

The Buddha was staying at Sāvatthī. At that time, women from the Sakyan, Mallan, and Licchavi clans had gone forth. They spun thread and sold it. Laypeople blamed them: “These aren’t renunciates, they’re just thread vendors.” For this reason, the bhikkhunīs went and informed … The Buddha said: “From now on, it’s no longer allowed to spin thread. ‘Spinning thread’ means cotton, linen, silk, sunn hemp, or hemp thread. (If a bhikkhunī) spins thread, and sells it to make a living, she breaks a minor vinaya rule. If she wants to make a water filter or a belt, and spins, there’s no offense.” This is called the rule on spinning thread.