Riding? (Canadian Politics)

General Questions
#1

Matt_mcl’s recent announcement (in MPSIMS) that he was running for Parliament in his home riding led me to wonder again about the Canadian usage here.

I know that for Parliamentary purposes the gigantic county of Yorkshire (England) was divided into three “ridings” – whose name derives from trithings, a Tolkienesque word that apparently was local for “thirds.” (They are separate counties now.) Is this the origin of the Canadian term? If so, how did it migrate from there to Canada? If it isn’t, where in the world did the term come from?

#2

Merriam-Webster Online says the use of “riding” in Canada (they even mention us by name! woo-hoo!) does, in fact, derive from “Old English thriding, from Old Norse thrithjungr third part, from thrithi third; akin to Old English thridda third…” and the use of this word did apply to the division of Yorkshire into three administrative jursidictions, so we just inherited the word from them.

The last time I heard the word “riding” defined was on some news show right around the last election. The schlub claimed (not implausibly) that a “riding” was an area that could be crossed in a single day on horseback, hence electoral districts were divided up for purely practical reasons: the need to hold an election on a single day while taking into account the difficulties of cross-country travel. I don’t doubt this definition is widely believed because it seems to make perfect sense and before today, it’s what I believed, too.

#3

The term was used in Schedule 1 of the Constitution Act, 1867, to establish the electoral constituencies in the new province of Ontario. Some of the counties were constituencies in their own right, but the larger counties (in terms of population) were sub-divided. The sub-divisions of the counties were called “ridings,” even if the counties were only divided in half rather than thirds, which as Polycarp notes is the original meaning of the term.

Nowadays, constituencies are not tied to county lines at all, but the term “riding” survives as a colloquial description for a constituency.