The Collaborative International Dictionary
Blackfriar \Blackfriar\, Black friar \Black" fri`ar\ (Eccl.) A friar of the Dominican order, so named becaise wearing wearing the black mantle of the Dominicans; -- called also predicant and preaching friar; in France, Jacobin. Also, sometimes, a Benedictine.
Syn: Dominican.
Douglas Harper's Etymology Dictionary
"Dominican," c.1500, so called from the color of their dress.
Wiktionary
alt. A member of the religious order of the Dominicans. n. A member of the religious order of the Dominicans.
Usage examples of "black friar".
I had to revise it twice, but it was not to be another Black Friar of the Flame.
The fate of 'Pilgrimage' (soon to become 'Black Friar of the Flame') was still rankling, and I wanted to write another future-historical.
But now he wondered how many of his erstwhile hosts were left in London, or how the young men might manage to gather together, if they were still so inclined, and worst yet, what the dining might be like in the upstairs room of the Black Friar pub, which was near Blackfriars Bridge and just upwind of the Thames.
The inn was called The Black Friar and it stood upon the banks of a broad but shallow river.