Freedmen

"Is it any wonder, then, that the slaves and freedmen have turned, in such great numbers, to the priests who preach of a cleansing fire?"

- Varys

Freedmen are former slaves in the Free Cities.

In the books
In the A Song of Ice and Fire novels, the ferm "freedmen" refers to slaves from Astapor, Yunkai and Meereen who were freed by Daenerys Targaryen.