What do you mean 'equivalent terms'?

Not all text-books or lecturers use the same terms or words to describe things. You need to know which terms mean the same thing. For example, if you know that the words 'football' and 'soccer' refer to the same game then you are unlikely to be confused by them. BUT, if you do not realise that they are 'equivalent terms' then you may very well become confused.

If you are able to recognise which terms are equivalent will you find this whole area very much easier to come to grips with.