Real Dictionary

standard
a continuously bending line that has no straight parts [...]
A standard work or text on a particular subject is one that is widely read and often recommended.
an accepted or approved example of something against which others are judged or measured [...]
the total of the inherited ideas, beliefs, values, and knowledge, which constitute the shared bases of social action [...]
You use standard to describe things which are usual and normal.
countable noun: A standard is a level of quality or achievement, especially a level that is thought to be acceptable.
countable noun: A standard is something that you use in order to judge the quality of something else.
plural noun: Standards are moral principles which affect people's attitudes and behaviour.