This collection of c. 250 dictionaries consists of a 1916 bequest by R. Oliver Heslop, philologist and antiquary, together with a few later additions. It includes Baret's Alvearie (1580), Florio's Worlde of Wordes (1598 and 1611), Minsheu's Guide into Tongues (1625 and 1627), the works of such lexicographers as Bullokar, Coles, Holyoake and Johnson, and an almost complete set of the publications of the English Dialect Society.

This collection also contains papers comprising Heslop's research material for his work Northumberland Words, published by the English Dialect Society in 1892-1894.