The words Poincare and Lorentz sound pretty elegant. I think they are French words like Loreal Or Laurent. I know Poincare has to do with spacetime translation and Lorentz with rotations symmetry. But how come one commonly heard about Lorentz symmetry in Special Relativity and General Relativity and rarely of Poincare symmetry. Yet in Quantum Field Theory, Poincare invariance seems to be more used than lorentz invariance. Would anyone happen to know why? Thanks.