big
The German word 'groß' is used to describe something as being large or big. It is an adjective and can be used to describe both physical size and abstract concepts. For example, you can say 'ein großes Haus' (a big house) or 'eine große Idee' (a big idea). It is important to note that the adjective 'groß' can also be used as a noun to refer to someone who is important or influential, as in 'ein großer Mann' (a great man).
The castle is very big.
This phrase indicates a commentary about the size of a certain structure - in this case, a castle, implying it's larger than average.
My brother is taller than me.
This phrase uses 'größer' (comparative form of 'groß') to make a comparison between the speaker and their brother's height.
This is a big opportunity.
Here, 'groß' is used metaphorically to describe the significance or potential benefit of the opportunity, rather than a physical size.