sane: [17] Latin sānus, a word of uncertain origin, meant ‘healthy’ – a connotation perpetuated in its derivative sanatorium ‘sickroom’ [19]. Its use with reference to mental rather than physical health (as in the Latin tag mēns sāna in corpore sāno ‘a healthy mind in a healthy body’) led to its adoption in English for ‘of sound mind, not mad’. => sanatorium, sanitary[sane etymology, sane origin, 英语词源]