Kent Online Parish Clerks
The Answer - 'Junior' or 'younger'
The terms "senior" and "junior" were largely used to distinguish two individuals from the same immediate family, e.g. father and son, or, mother and daughter, respectively. Yes, I have seen the distinction used to differentiate two woman in the same household who bore the same Christian name.
There is, however, an additional qualification that I have encountered in many records - the distinction of "the elder" and "the younger". In the majority of cases, this distinction has been used to differentiate between two people of the same parish bearing the same name but who were not father and son, e.g. uncle and nephew, or, two cousins one of whom was older or younger than the other. Again, I have seen this distinction used to differentiate between woman of the same name.
I have also seen both types of references used in the alternately occurring case. That is to say, I have encountered "the elder" with "the younger" representing provable father and son. Likewise, I have encountered "senior" with "junior" representing the family of an uncle and the family of that uncle's nephew. And, I have encountered the terms "the elder" and "the younger" used to distinguish between two sons of the same name in the same immediately family. The proof of this latter claim is contained in a Will of a Carter family from mid-east Kent. The father, having married twice, had two sons each named John, but borne of different wives. Mr. Carter used the term "the elder" to refer to his son by his first wife and "the younger" to refer to his son by the second wife. Both sons were living at the time the Will was drawn and were both still living at the time of their father's death and subsequent proving of the father's Will.
This all goes to show that nothing is "carved in stone" in this pursuit.