Is it farther or further?
1823, "pertaining to health," from French sanitaire (1812), from Latin sanitas "health," from sanus "healthy; sane" (see sane). In reference to menstrual pads, first attested 1881 (in sanitary towel).
sanitary san·i·tar·y (sān'ĭ-těr'ē)
Of or relating to health.
Free from elements, such as filth or pathogens, that endanger health; hygienic.