Valuations — morphisms from (σ*, ·, e) to ((0, ∞), ·, 1) —are a generalization of Bernoulli morphisms introduced in [7]. Here, we show how to generalize the notion of entropy (of a language) in order to obtain new formulae to determine the Hausdorff dimension of fractal sets (also in Euclidean spaces) especially defined via regular Ω-languages. In this way, we can sharpen and generalize earlier results [1,10,11,20,29].