standard
An accepted level of quality used to judge something.
A standard is an established level of quality, achievement, or behavior that serves as a measuring point or goal. When a teacher sets high standards for homework, the teacher expects careful, thorough work, not sloppy efforts dashed off in five minutes. When a restaurant maintains high standards for its food, every dish that leaves the kitchen meets specific requirements for taste, temperature, and presentation.
Standards help us know what's expected and what counts as good enough. A building code sets standards for how strong a house's foundation must be. Academic standards define what students should learn in each grade. Personal standards are the rules you set for yourself: maybe you have a standard of always telling the truth, or never turning in work you're not proud of.
The word also means typical or commonly used. A standard deck of cards has 52 cards. Standard operating procedure means the normal way something is done.
When something becomes the standard, it becomes the version most people use or accept. For decades, the QWERTY keyboard has been the standard layout, even though other designs exist. In manufacturing, parts are often made to standard sizes so they fit together reliably.
Having standards means having expectations. A person with no standards accepts anything, good or bad. A person with standards knows what they're aiming for, and tries to live up to it.