Definition of "dialectal"

Now (exc. in Nautical language, see b) it is only dialectal or an illiterate substitute for lie, its identity of form with the past tense of the latter no doubt accounting largely for the confusion.

1908, “lay v.¹”, in James A. H. Murray et al., editors, A New English Dictionary on Historical Principles (Oxford English Dictionary), volume VI, Part 1, London: Clarendon Press, page 128