I thought its a typo for program or something, turns out it's a real word:

A pogrom is a violent riot incited with the aim of massacring or expelling an ethnic or religious group

an organized massacre of helpless people

Essentially, (if my high school history had it correct) it's an extreme form of violence designed to force a targeted people to leave the land they are living on. People used to use this term a lot more in older days (back in the 80s), but now we just use the term genocide since pogroms usually are an aspect of genocide - the Armenian Genocide, for instance, had a lot of pogroms going on. They are also a key aspect of settler-colonialism - which is how Palestinians ended up being one of the largest refugee populations in the world.

@shasta technically speaking it's organized violent persecution of an ethnic group. Historically has a more specific meaning as it originates in Russia.

When the Russian Empire expanded and in the 19th century began to colonize /occupy territory that contained significant ethnic Jewish populations, they undertook a lot of rioting to lynch/massacre/expell them. These were known as "pogroms".

In modern English it means this kind of systematic attack against any ethnic group. It is also sometimes used informally/metaphorically for other things e.g. political or corporate "pogroms" against a particular group or class of people.