1) A strong beam used in the construction of bridges, houses, mills etc.
References in the OED date from 1607 but in Yorkshire the term has been noted only from the eighteenth century. Accounts relating to Batley Bridge include: 1733 the long pieces … to be three in number … all of heart of oak and the sleepers, or cross pieces at the ends … of yew or good oak . In unpublished documents for Cawood there were requests by tenants in 1756 for new Slepers for the mill and Sleepers … which shou’d be 10 Inches deep for a barn floor. In 1786, William Metcalfe of Sessay, near Thirsk, wrote in his diary: Leading sleepers from the wood. In areas where there were collieries, a sleeper was a piece of timber used as a transverse support for the rails of a tramway or railway: 1817 Moses Barker for sleepers, Halifax. The word can be compared with ‘dorman, dormand’.