The three letters of the root for Zulm are: Zaa, Laam and Meem. And it occurs in the Quran 315 times, in 12 different derivative forms.
A) Two Hundred and Eighty Nine or so of these are where the meaning refers to committing all kinds of atrocities and injustices. And they are:
1) 110 times as Zalama -- He committed Zulm.
2) 16 times as comparative degree Azlam -- More Zaalim.
3) Twice as noun masculine plural Zaalimee -- Those who commit Zulm.
4) Five times as noun for hyperbole Zallaam -- Someone most given to committing Zulm.
5) 20 times as abstract noun Zulm -- Tyranny, oppression and all kinds of atrocities.
6) Twice as another form of hyperbole Zaloom -- Most given to Zulm.
7) 129 times as adjective masculine Zaalim -- One who commits Zulm.
8) Four times as adjective feminine Zaalimah -- Female committing Zulm.
9) Once as passive Mazloom -- Someone subjected to Zulm.
B) Other than that, three of the occurrences of the root ZLM in the Qur'an yield words that refer to darkness. And they are:
1) Twice as adjective Muzlim -- Dark.
2) 23 times as noun, feminine, plural, Zulumaat -- Darknesses.
3) Once as verb Azlama -- It became dark.
No wonder Islam is so dead set against all forms of tyranny, oppression and injustice.
And Muslims, wherever and whenever they had the upper hand, established justice and equality and fairness in the land, which made the oppressed people of the world flock to Islam in droves.