mat, matting
茣 centers on woven floor coverings: a mat or matting, typically made from plant material.
茣 combines the grass radical 艹 with 吳, which likely contributes the sound. The character is used for woven grass mats.
The top 艹 suggests plant material, and the bottom 吳 looks like a woven grid. Picture grass fibers woven into a flat mat.
For ゴ, imagine a mat made of go-lden straw: go -> ゴ, and the golden mat lies under the grass top.
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