texlinear density · International textile / SI-compatible · Modern standardized1 tex = 1 gram per 1000 metres = 1 mg/m = 10^-6 kg/m.
denierlinear density · Textile / hosiery / fibers · Historical-modern standardized convention1 denier = 1 gram per 9000 metres = 1/9 tex ≈ 0.111111 tex.