fine woolen fabrics
羢 centers on fine woolen fabrics, specifically a type of soft, high-quality wool or woolen cloth.
羢 combines 羊 (sheep) with 戎, which likely contributes the sound. The character is used for fine woolen fabrics, reflecting the sheep component.
Sheep 羊 provide the wool, and the right side 戎 looks like a woven pattern. Picture a sheep wearing a finely woven woolen garment.
For ジョウ, imagine a soft woolen fabric being woven on a loom with a gentle 'joh' sound: joh -> ジョウ, as the sheep's wool becomes fine cloth.