From the JewishGen Website:
Reading Jewish Tombstones
Jewish tombstones with Hebrew inscriptions have an added value to genealogists, in that they not only show the date of death and sometimes the age or date of birth, but they also include the given name of the deceased's father. This permits you to go back one more generation.
Here are a few helpful pointers if you cannot read Hebrew.
At the top of most Jewish tombstones is the abbreviation פּ'נ, which stands for po nikbaror po nitman, meaning “here lies”.
At the end of many Hebrew tombstone inscriptions you will find the abbreviation ת נ צ ב ה, which is an abbreviation of a verse from the Bible, the first book of Samuel, 25:29, “May his soul be bound up in the bond of eternal life”.
If any Hebrew characters at all are written on a tombstone, they are most likely to be the person's Hebrew name. A Hebrew name always includes a patronymic, the person's father's given name. This is a unique feature of Jewish tombstones, and a great boon to Jewish genealogy.
The Hebrew word בן, ben, means “son of”, as in “Yaakov ben Yitzhak”, meaning “Yaakov, the son of Yitzhak”. The Hebrew word בת, bat, means “daughter of”. On tombstones, these words will often appear as ב'ר, an abbreviation forben reb, meaning “son (or daughter) of the worthy”, followed by the father's given name. The word reb is a simple honorific, a title of respect, akin to “Mr.” — it does not mean Rabbi.
There is much more on the webpage. See https://www.jewishgen.org/infofiles/tombstones.html