According to Jewish tradition, the term "patriarchs" refers to Abraham, Isaac, and Jacob because "only three are called patriarchs."
All the tribes of Israel descended from Jacob. All the tribes, called "the tribes of the Almighty," share one father and one genealogy. Sometimes the word "Avot" refers to a section of the Mishnah that contains the sayings of our sages over a period of over 500 years.
The first blessing of the Shemona Esrei prayer, which mentions Abraham, Isaac, and Jacob, is also called "Avot."