en_tn/jdg/16/21.md

put out his eyes

This means that they removed his eyes from his head. Alternate translation: "removed his eyes" (See: rc://en/ta/man/jit/figs-idiom)

down to Gaza

The phrase "down to" is used here because they brought Samson to Gaza which is lower in elevation than his home where they captured him.

bound him with bronze shackles

"chained him with bronze shackles" or "tied him up using bronze shackles"

shackles

locks on the end of chains that hold a prisoner at his feet or hands, or both

turned the millstone

"pulled the millstone around in a circle"

millstone

This is a very large, heavy, circular stone. Normally, a large animal pulls the millstone around in a circle to crush grain. Here the Philistines humiliate Samson by making him pull it.