The third mission of universities has various definitions but includes everything done by universities in addition to research and teaching. Terms I have come across are community engagement, socialisation of knowledge, contract R&D. There was an interesting paper a few years ago which listed more that 15 impact pathways for universities. So you can take your pick of the number of missions .. let's just say that universities in the 21st century do more than teaching and research, which is important and to be encouraged up to a certain limit. The latter is what we may all disagree upon.