Actually it was given in test plan where the test lead 
decides what are the feautures to be tested in the 
application and what type of testing to be done for example 
in the given project there are two module where you were 
asked to test particular module which u have to test which 
is called features to be tested and the remaining are 
features not to be tested thank u as per my knowledge

in test plan
features to be tested : features means modules.what are the
responsible modules of the build for complete testing.

features not to be tested:
     generally test eng concentrates on all the module's 
functionality of the project.but in a few cases like
enhancement projects or the project with third party
involvement,in this cases testing team concentrates on only
required functionality but not on all module's functionality.