James Johnston's Place-names of Scotland postulates a Gaelic etymology, from earr an achaidh "end/boundary of the field".

Simon Robertoun regained Earnock through marriage to a daughter of David fitz Walter of Cadzow (Beverage nd) (Nesbitt A nd) ).

It was sold by James Roberton, 12th Laird of Earnock, to a Mr Semple at the turn of the 19th century.

Earnockmuir, part of the original estate was inherited by Sir William Erskine Cochrane,(Hamilton Advertiser 1874) (brother of Lord Dundonald) great grandson of the last Laird of Earnock.

(Stothers nd) When John Roberton of Glasgow settled in New Zealand in the 19th century he named his Takapuna property "Earnock", after the family estate in Scotland.