We typically focus on seven (7), key terms and refer to this as a topic. For e.g., the topic can be 'dentist'  and the keyterms could be dentist, dentists, teeth whitening, implants, invisalign, etc.  However, the dentist may want to specifically focus on variations of 'invisalign" or 'implants' if that is their best profit margin, which could each be it's own topic if they really want to get granular.