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 whether 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.
For a discussion of where understanding takes place and the what the limits of understanding are, see the Chinese Room argument.
Understanding is also the name of a poem by Andrew Bottomley shown below
Understanding Don't have a clue About where to go About what to do Life forced upon me From the gloomiest place Look in the mirror Can't see my face Lost in the sadness Lost in the dark Its finally over The end of life's lark
Moreover, Gardner (1991) argues that students' understanding of the humanistic subject matters is plagued by a number of stereotypes--for instance those concerning racial, sexual, and ethnic identity--that amount to misunderstandings of the human condition in its variety.
In summary, understanding something is a matter of being able to carry out a variety of "performances" concerning the topic--performances like making predictions about the snowball fight in space that show one's understanding and, at the same time, advance it by encompassing new situations.
Analyses of understanding emphasize that concepts and principles in a discipline are not understood in isolation (Perkins, 1992; Perkins and Simmons, 1988; Schwab, 1978).