Definition of "coated"

I can just remember an old brown-coated man who was the Walton of this stream, who had come over from Newcastle, England, with his son, the latter a stout and hearty man who had lifted an anchor in his day.

1849 December, “A Week on the Concord and Merrimack Rivers. […]”, in The Massachusetts Quarterly Review, number IX, Boston, Mass.: […] Coolidge & Wiley, […], page 51

Was sitting on a molar cusp nibbling a remnant of dry toast, when I looked out and saw a white-coated man with a shiney instrument in his hand.

1908, The Practical Dental Journal, page 2

A few seconds after photograph 17 was taken; note that the coated woman has stopped to chat to the group.

1963, The Journal of the Royal Institute of Public Health and Hygiene, page 51, column 1