(nautical) A block fixed in the topgallant or royal rigging, used for raising and lowering light masts and spars.

In a hip roof, a minor truss used where the roof does not have its full section.

copper sulphate

plural of jack-a-napes

plural of jack-a-lantern

In brewing and malt vinegar manufacture, a cistern which receives the wort.

(knitting machines) A thin iron plate operated by the jack to depress the loop of thread between two needles.

(architecture) Any timber, such as a rafter, rib, or studding, which, being intercepted, is shorter than the others.

(informal) A person who vocalizes quietly, in a whispering manner, or, ironically, one who is loud and outspoken.

Alternative form of Jack-in-the-pulpit