jewel block

plural jewel blocks · alternative jewel-block

1. archaicnauticalA block at the extremity of a yard, through which the halyard of a studdingsail is rove.

   1 more example

   Having reeved the line through all the inferior blocks, I went out with it to the end of the weather-top-gallant-yard-arm, and was in the act of leaning over and passing it through the suspended jewel-block there, when the ship gave a plunge in the sudden swells of the calm sea, and pitching me still further over the yard, threw the heavy skirts of my jacket right over my head, completely muffling me

   1850, Herman Melville, White-Jacket