Definition of "dirk"

The Claymore is worn on the left side, the dirk on the right, and the Skean Dhu in the stocking […]

1898, W.D.F Vincent, The Cutters' Practical Guide

In half a minute he had reached the port scuppers, and picked, out of a coil of rope, a long knife, or rather a short dirk, discolored to the hilt with blood.

1881–1882, Robert Louis Stevenson, Treasure Island, London, Paris: Cassell & Company, published 14 November 1883

In this kit was the ‘Officer of the Watch’ telescope from Dolland and Sons, presented to me by my godmother, Inman's Nautical Tables, a parallel ruler, and, of course, a dirk.

1996, Frank Twiss, Social Change in the Royal Navy, 1924–1970

The word dick itself serves as model for two variants which are probably Midwestern, dirk and dork, also meaning "penis"...

May 1964, Lawrence Poston, "Some Problems in the Study of Campus Slang", American Speech volume 39, issue 2

...on at least one Midwestern campus a dirk may be an "oddball" student, while a prick (more common) is of course an offensive one.

May 1964, Lawrence Poston, "Some Problems in the Study of Campus Slang", American Speech volume 39, issue 2

Roland Graeme has dirked Adam Woodstock — that is all.” ¶ “Good Heaven!” said the Lady, turning pale as ashes, “is the man slain?”

1820, Sir Walter Scott, The Abbot‎, archived from the original on 4 June 2014, Chapter the Fourth

For these offenses, I was informed privately, by a worthy English settler, who had been like me seduced by Mr. Birkbeck, they had hired a man to dirk me for ten dollars, the usual price of blood in this country, as Mr. Chichester says.

1825, James Kirke Paulding, John Bull in America; or, the New Munchausen‎, page 127

Thy wast bignes but combers the grownd, / And dirks the beauty of my blossomes rownd.

1579, Edmund Spenser, The Shepheardes Calender‎, page 34