Substantial part
Copyright is infringed where either the whole or a substantial part of a work is used without permission, unless the copying falls within the scope of one of the copyright exceptions.
A substantial part is not defined in copyright law but has been interpreted by the courts to mean a qualitatively significant part of a work even where this is not a large part of the work. Therefore, it is quite likely that even a small portion of the whole work will still be a substantial part.
All the other economic rights also apply where the whole or a substantial part is to be used, but it is worth considering whether the use falls within the scope of any of the copyright exceptions.
