木綿・もめん・momen | 綿・めん・men
Cotton. Technically men is used for the raw product but in day-to-day conversation the terms momen and men are interchangeble. Cotton fabric.
Cotton was a cheaper, easier to manage and process, alternative to plant-based fibers. It became the basic fabric in the Edo period replacing asa (hemp, ramie).
Wata (another reading of the same Japanese character 綿, わた) refers to (raw) cotton used as-is, not spun into threads. Wata is used as a stuffing/batting in futon (bedding) and winter clothing.