Understanding is a psychological state in relation to an object or person whereby one is able to think about it and use concepts to be able to deal adequately with that object.

For example, I understand the weather if I am able to predict and give an explanation of some of its features.

Or, a psychiatrist understands another person if he knows his anxieties and their causes, and can give him useful advice on how to minimise the anxiety.

I understand a command if I know who gave it, what is expected, and whether the command is legitimate.

Also one can understand a reasoning, an argument, and a language.

See also knowledge, epistemology, and thought.