Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
conserve [kənˈsəːv] vt (preserve) сохраня́ть (сохрани́ть perf) (energy) рациона́льно испо́льзовать (impf)
n варе́нье#
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.