See the practical article by a lawyer seeking gTLD application clients.
Good background on the issue, that will give you the terminology and issues to consider regarding ICANN’s expanded top level domain scheme.
Before choosing an attorney, try Google to see who is writing with the focus on clients like you. Attorneys generally either love or hate this new rash of gTLDs and generally either represent established legitimate companies or new fast buck artists seeking advantage from the confusion over this new scheme of domain names. Get a knowledgable attorney to help you, as there are deadlines and special forms involved and you need expert advice on whether it makes sense for your business.