1723 D. Baker Let. 29 Jan. in (1965) 148 The best pits of coal..are as good as prohibited by a lock duty in the Bill of 10s. per tunn.
1805 Mar. 290/1 Her husband was absent, having just gone on shore to pay the lock-duties.
1992 R. Stone in M. Fry iv. 67 The toll or lock duty can be the property of an individual.