synaptogenesis

noun
syn·​ap·​to·​gen·​e·​sis | \ sə-ˌnap-tə-ˈjen-ə-səs How to pronounce synaptogenesis (audio) \
plural synaptogeneses\ -​ˌsēz How to pronounce synaptogeneses (audio) \

Medical Definition of synaptogenesis

: the formation of nerve synapses