1829, "an improper form for sanatorium" [Century Dictionary], meant to indicate "place dedicated to health," perhaps based on sanitary or from Latin sanitas "health," from sanus "healthy; sane" (see sane).
Entries linking to sanitarium
sanatorium n.
by 1839 as "hospital, usually private, for the treatment of invalids, convalescents, etc., who might benefit from open air;" by 1842 as "place to which people go for the sake of health or to regain health;" Modern Latin, noun use of neuter of Late Latin adjective sanitorius "health-giving," from Latin sanat-, past-participle stem of sanare "to heal," from sanus "well, healthy, sane" (see sane).
Latin sanare is the source of Italian sanare, Spanish sanar. Century Dictionary [1895] notes it was "specifically applied to military stations on the mountains or tablelands of tropical countries, with climates suited to the health of Europeans."
Many of his patients had asked him what this hard word sanatorium meant, and he explained to them, that it was a lodging-house, which was, in fact, the proper alias of sanatorium, and that it was to the benefit of Dr. Arnott's stove and of regularity in the time of giving medicine. [from report on a "Debate on the Sanatorium" in The Lancet, Jan. 11, 1840]
sanitary adj.
1823, "pertaining to health or hygiene," from French sanitaire (1812), from Latin sanitas "health," from sanus "healthy; sane" (see sane). In reference to menstrual devices, by 1881 (in sanitary towel). In U.S. history the Sanitary Commission, created by the Secretary of War in 1861, provided relief to soldiers and oversaw military lodging and hospitals. Sanitarian is by 1859 as "promoter of, or one versed in, sanitary measures or reforms;" sanitarist in that sense also is by 1859.
sane adj.
"of sound mind, mentally sound," 1721, a back-formation from insane or sanity or else from Latin sanus "sound, healthy," in its figurative or transferred use, "of sound mind, rational, sane," also, of style, "correct;" a word of uncertain origin.
It is perhaps from PIE *seh-no- from *seh- "to tie." That reconstruction "is purely mechanical," according to de Vaan, the meaning might be "which is in place, in order." Or it could be from a different root meaning "to satisfy" as in Latin satis "enough."
Used earlier, of the body, with a sense of "healthy" (1620s), but this has been rare in English. OED writes, "The almost entire restriction in English to a sense 'mentally sound' is due to the use in antithesis with insane, which (like the Latin insanus, its source) always referred to mental condition." Related: Sanely; saneness.