jack block
noun Nautical.
a block used in raising or lowering a topgallant yard.
Nearby words
jacaré, jacinth, jack, jack arch, jack bean, jack block, jack chain, jack crevalle, jack crosstree, jack frost, jack in
Origin of jack block
First recorded in 1785–95
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019