We study dynamical systems given by the action T : G × X → X of a finitely generated semigroup G with identity 1 on a compact metric space X by continuous selfmaps and with T (1, −) = idX .For any finite generating set G1 of G containing 1, the receptive topological entropy of G1 (in the sense of Ghys et al. (1988) andHofmann andStoyanov (1995)) is shown to coincide with the limit of upper capacities of dynamically defined Carathéodory structures on X depending on G1, and a similar result holds true for the classical topological entropy when G is amenable. Moreover, the receptive topological entropy and the topological entropy of G1 are lower bounded by respective generalizations of Katok's δ-measure entropy, for δ ∈ (0, 1).In the case when T (g, −) is a locally expanding selfmap of X for every g ∈ G \ {1}, we show that the receptive topological entropy of G1 dominates the Hausdorff dimension of X modulo a factor log λ determined by the expanding coefficients of the elements of {T (g, −) : g ∈ G1 \ {1}}.