Webster's Revised Unabridged Dictionary · 1913

Dak

Dak (dak or dak) , noun

[Hind. dāk.]

Post; mail; also, the mail or postal arrangements; -- spelt also dawk, and dauk. [India]
Collocations (3)
Dak boat , a mail boat. — Percy Smith
Dak bungalow , a traveler's rest-house at the end of a dak stage.
To travel by dak , to travel by relays of palanquins or other carriage, as fast as the post along a road.