n. A professional firefighter who also works as a volunteer firefighter, usually in a rural area.
2014
No one knows how many double-hatters Ontario has — most are quiet about their off-duty work for fear of provoking union leaders — but it is estimated there are hundreds among the 19,000 men and women who take time off their regular jobs to respond to fires, crashes and medical emergencies in small communities.
2014
Like the other three full-time Waterloo firefighters who worked part-time in Wellesley, also known as "double hatters," Steinman left the rural fire department because of a concern over additional compensation benefits if he were to get sick.
2001 (earliest)
On Sept. 4, the volunteer forces lost the last of the "double-hatters:" professional fire fighters who volunteered in rural departments during their own time.