The Collaborative International Dictionary
Ductor \Duc"tor\, n. [L., fr. ducere to lead.]
One who leads. [Obs.]
--Sir T. Browne.-
(Mach.) A contrivance for removing superfluous ink or coloring matter from a roller. See Doctor, 4.
--Knight.Ductor roller (Printing), the roller which conveys or supplies ink to another roller.
--Knight.
Wiktionary
n. 1 (context obsolete English) One who leads. 2 (context printing English) A device, usually in the form of an oscillating roller, for transferring ink from a source to the ink train rollers in a controlled manner. See also (term: doctor).
Wikipedia
Ductor is an extinct genus of prehistoric bony fish that lived from the early to middle Eocene. Fossils have been found in Monte Bolca.
In life, species of Ductor would have resembled pilot fish, though, they are more closely related to the jackfish. Some experts place Ductor into its own family, "Ductoridae," while others place the genus within the closely related Carangidae.
Usage examples of "ductor".
The Ductor Dubitantium has a deep chapter on 'The Thinking Conscience.
Their con ductors, or "cads", had a reputation for violence and obscenity which lingers in the word to this day.