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"Naut.: A square bar of wood or iron, with a shoulder at one end, used to support a topmast or topgallantmast when swayed up into place. The fid passes through a square hole in the heel of its mast, and its ends rest on the trestletrees." -Whitney, 1911

Mast Fid

"Naut.: A square bar of wood or iron, with a shoulder at one end, used to support a topmast or topgallantmast…

"A conical pin of hard wood, from 12 to 24 inches long, and from 1 to 3 inches in diameter at the butt, used to open the strands of rope in splicing." -Whitney, 1911

Setting Fid

"A conical pin of hard wood, from 12 to 24 inches long, and from 1 to 3 inches in diameter at the butt,…