Idiomatic expression that serves as a reminder to behave courteously or to follow the social and cultural norms and practices of polite society. It is often used by adults to remind children of proper behavior, but can also be used among adults as a way to subtly nudge someone into behaving appropriately in a given social setting.
Its elements can be traced back to older linguistic constructs. "Mind" is used as a verb that means to "pay attention to" or "be aware of. "This usage has its roots in Old English, where "mind" or "gemynd" had meanings related to memory, thought, and attention. "Manners" comes from the Latin "manuarius," meaning "belonging to the hand," which evolved into the idea of something being 'handy' or 'manual.' The phrase has been in usage for quite some time and encapsulates a value that has been deemed important across many cultures and eras: the practice of social etiquette.