half
The German word 'halb' is used to describe something as being half or partially done. It can be used as an adverb, adjective, or noun. For example, 'Ich habe das Buch halb gelesen' means 'I have read half of the book'. It can also be used in mathematical contexts, such as 'Die Hälfte von sechs ist drei' which means 'Half of six is three'.
It is half past two.
The time expressions in German can be a bit tricky. 'Halb drei' translates directly as 'half three', but what it really means is 'halfway to three', so in English it is expressed as 'half past two'.
I have only read half of the book.
In this case, 'halb' is used to denote a part of a whole. 'Nur halb gelesen' means 'only half read', indicating that the speaker only completed 50% of the book.
He is half German, half American.
When talking about dual nationality, you can use 'halb' to express this. The phrase 'Er ist halb Deutscher, halb Amerikaner' means 'He is half German, half American', speaking about the person's heritage.