This is the 9019th most frequent Russian word.
римско
"Rимско" translates to "Roman" in English.
The adjective "римско" (roman) in this context modifies "католическая церковь" (Catholic Church) to specify its relation to Rome, indicating the church branch based in Rome.
Римско-католическая церковь является крупнейшей христианской деноминацией.
The Roman Catholic Church is the largest Christian denomination.
Here, "римско" combines with "греческую" to form a compound adjective describing the dual cultural aspects—Roman and Greek.
Он изучал римско-греческую культуру в университете.
He studied Roman-Greek culture at the university.
In this sentence, "римско" characterizes "гончарные изделия" (pottery) as being of Roman origin or style.