Green’s Dictionary of Slang

Jock n.

[the stereotypical Scot. given name Jock, f. John]

1. [mid-18C–19C] a Northcountry seaman, esp. a crewman of a collier.

2. [mid-18C+] (also Jockey, Jockie, Jocky) a generic term for a Scotsman.

3. [late 19C+] as a term of address to a Scot.

In compounds

Jockland (n.)

[2000s] Scotland.