For the hydrogen in palladium (PdH) system, the critical point has been located at T c= 566+ or-1K, rho c= 0.29+ or-0.01 atomic H/Pd ratio, P c= 19.89+ or-0.05 atm (hydrogen pressure surrounding the palladium). Critical-point exponents delta, gamma and Delta have been determined for the critical isotherm, the isothermal compressibility of the hydrogen lattice gas (this being proportional to the relaxation strength of the elastic after-effect for the interstitial hydrogen in the palladium) and the relaxation time of the elastic after-effect, respectively. The experimental values of these exponents (delta= 3.2+ or-0.3, gamma= 1.01+ or-0.01, Delta= 1.01+ or-0.1) and information from the specific heat measurements indicate that the critical-point behaviour of the PdH system is described by mean-field theory at least for epsilon=(TT c)/T c approximately= 10-3. This behaviour is compatible with the interaction between the interstitial hydrogens being a long-range elastic type between lattice defects in the palladium.