From Simple English Wikipedia, the free encyclopedia
This is a household plug. The variant with 2 pins is standard across most of the world.
The metal block is a copy of the prototype kilogram: Until it was redefined in 2019, everyone needed to compare to the prototype kilogram.
Light bulbs have standard sockets. There are a few socket types, which vary by use. Using a standard socket means that a lamp will accept all light bulbs with the same socket.

In order to be able to work together, people and companies need to agree on a common set of rules, and units. These agreements are called standards. The process of agreeing is called standardization or standardisation.

Companies that have products which follow these rules can make their products work together. One example of a standard is the two pin plug. It provides electricity. It is commonly found in household appliances. Many countries have adopted it. However, this is not the case for three-pin plugs: they are different in each country.

Agreements do not need to be technical. Lawyers can agree on a standard way to solve a problem, linguists can agree on what the "standard language" is, and bookkeepers can agree on rules how to evaluate a company.

Different USB connectors. USB is a standard to connect peripherals. It replaced many other plugs, and is commonly used.