Definition of "lubricator"

The mystery of the dripping lubricators was also explained to him.

1913, Arthur Conan Doyle, “(please specify the page)”, in The Poison Belt […], London; New York, N.Y.: Hodder and Stoughton

Valve and cylinder lubrication is by atomised oil delivered by mechanical lubricators.

1951 March, “British Railways Standard "Britannia" Class 4-6-2 Locomotives”, in Railway Magazine, page 186

The uniformity of the wheel diameters of diesel and electric locomotives and m.u. trains impairs the spreading of grease from one point fed by the lubricator and the growing traffic of m.u. trains and railcars has increased the need for lubrication and for check rails in certain places. The newer types of rail lubricator apply the grease at four or five points spaced so that the entire wheel flange is greased and even distribution ensured; [...].

1962 December, “Talking of Trains: Rail and flange lubrication”, in Modern Railways, page 372