Dipole and quadrupole excitations in the semimagic N=50 nucleus 88Sr were investigated at the superconducting Darmstadt electron linear accelerator S-DALINAC with bremsstrahlung of an end-point energy of 6.8 MeV . Many new dipole excitations could be identified, and their reduced excitation probabilities were determined. The experimental findings are discussed in the context of quasiparticle-phonon-model and shell-model calculations. A breaking of the N=50 core is essential to describe the structure of the observed excitations. The two-phonon quadrupole-octupole J?=1- state exhibits unusual features which are presently not understood.