By the Seder we say “Chamisho chumshei Torah, arba imahos, sh’loshl avos, etc” Seder Nezikin starts with “Arbo’o avos nezikin”, and there are only 3 bubes, Baba Kama, BabaMezia, and Baba Basra”. This is a setira to what we said “4 imahos and 3 avos”?
The teretz is: the Gemara says that in a house where there is an old woman, there is a blessing, since she helps with the children, mends clothes, and soothes the frazzled nerves. However, where there is an old man, it is a “CHARA” (not good) because he is always angry, he screams at everything and everyone.
Therefore, if there are 4 avos and 3 imahos (babas), it is REALLY NEZIKIN.
A second Wort, what do you call an old fat lady?
Baba Basra with a “sin”, not a “sav”.