mineral oil

machine; machinery

needed, necessary

need, necessity

器械: a device, an appliance, a mechanism / 機械: a machine, equipment, an apparatus / 器械: a utensil, a tool, an instrument / 器械: a tool for conducting a test or experiment or for measurement

necessary evil

necessity (quality or state of being necessary, unavoidable, or absolutely requisite)

unnecessary

needlessness

Synonym of プリンター (purintā, “printer”)