1658 Exemplification St Ives Law Sewers 18 Mar. in C. N. Cole Coll. Laws Bedford Level Corporation (1761) 204 The same [one hundred seventy-eight Acres] is already set out, and by Lockspits or small Trenches severed and divided from the Residue of the said Fens.

1704 J. Harris Lexicon Technicum I Lock-spit, a Term in Fortification, signifying the small Cut or Trench made with a Spade, to mark out the first Lines of any Work that is to be made.

1753 Chambers's Cycl. Suppl. Lockspit, among miners, is the small cut or trench made with a spade of about a foot wide, to mark out the first lines of a work.

1889 E. Peacock Gloss. Words Manley & Corringham, Lincs. (ed. 2) Lockspit, a breadth of earth taken from the bottom of a drain of the same width as an ordinary draining tool.

1902 Jrnl. Soc. Arts 30 May 604/1 When the cross-lines mentioned have been laid out, it is only necessary to join the points forming the corners of squares by lockspits parallel to the base..to complete each square.

1998 Canberra Times (Nexis) 15 Jan. a3 Sometimes Mr Lavis searches for old pegs and lockspits—trenches marking boundaries.

1687 J. Taylor Thesaurarium Mathematicae xiii. §iii. 286 Lock-spit out the Flanks CF, and the Faces AF,..so is the Fort lined out for the Ground-line.

1767 Glamis Estate Papers MSS in Sc. National Dict. (1965) VI. 116/3 Lockspitting and evening the foundation.

1849 Trans. Inst. Civil Engineers Ireland 3 45 The centre line of the proposed cut was laid out, and lockspitted across the bog, on the 9th September, 1846.

1889 E. Peacock Gloss. Words Manley & Corringham, Lincs. (ed. 2) (at cited word) I lockspitted her oot fra one end to t'uther.

1901 Maitland (New S. Wales) Daily Mercury 2 Dec. The [railway] line had also been surveyed, trial-holed and lock-spitted.

1968 OECD Agric. Rev. 15 78/1 A Surveyor goes on the ground and lockspits the boundaries of the several plots.