. "The chemical reactions and pathways resulting in the formation of one of a family of organic molecules consisting of a pyrimidine base covalently bonded to a sugar ribose (a ribonucleoside) or deoxyribose (a deoxyribonucleoside)." . . . . "pyrimidine nucleoside biosynthetic process" . "pyrimidine nucleoside anabolism" . "pyrimidine nucleoside biosynthesis" . "pyrimidine nucleoside formation" . "pyrimidine nucleoside synthesis" . . . . . .