Final answer:
In the context provided, 'dubbed' means given a nickname or named. It refers to a skateboarding trick being popularly called 'the impossible' within the community.
Step-by-step explanation:
In the passage provided, the word dubbed means given a nickname or named. It suggests that a certain trick in skateboarding has been referred to as the 'impossible' not officially, but by popular usage or by the community that is familiar with it. This usage applies when a name has become commonly accepted among a group even though it's not an official term.
For example, a skater might invent a new trick, and over time, as the trick becomes well-known, it gets a unique name that people start using to refer to it. The term 'dubbed' indicates that the name started being used informally and then gained wider acceptance. 'To dub' can often be seen in contexts where something is being named in a ceremonial or significant way as well.