What does LG ^ 2 (3) mean? I mean the logarithm of 3 of LG ^ 2 with the base of 10

What does LG ^ 2 (3) mean? I mean the logarithm of 3 of LG ^ 2 with the base of 10

LG ^ 2 (3) = Lg3 × Lg3
≈0.4771×0.4771
≈0.2276