Why is the ninth month called September?
mid-14c., "self-restraint, moderation," from Anglo-French temperaunce (mid-13c.), from Latin temperantia "moderation," from temperans, present participle of temperare "to moderate" (see temper). Latin temperantia was used by Cicero to translate Greek sophrosyne "moderation." In English, temperance was used to render Latin continentia or abstinentia, specifically in reference to drinking alcohol and eating; hence by early 1800s it came to mean "abstinence from alcoholic drink."
temperance tem·per·ance (těm'pər-əns, těm'prəns)
Moderation and self-restraint, as in behavior or expression.
Restraint in the use of or abstinence from alcoholic liquors.