Legal drinking age. The legal drinking age is the age at which a person can legally consume or purchase alcoholic beverages. These laws cover a wide range of issues and behaviors, addressing when and where alcohol can be consumed.
An open system is a system that has external interactions. Such interactions can take the form of information, energy, or material transfers into or out of the system boundary, depending on the discipline which defines the concept.
The definition of an open circuit is  a broken path for an electrical current due to an open switch or frayed wire. An example of an open circuit is a string of electric lights that donât work if one bulb goes out.