Eggcorn Forum

Dozens of web writers think that ordnance survey maps are “ordernance survey” maps:

Goods for sale/exchange post: “does anyone have new or old landranger or ordernance survey maps”

Chalet guest book: “Really appreciated the ordernance survey map for local walks”

Landlord forum: “I am being told that the ordernance survey maps at land registry are not always correct”

Making a link between maps and order seems like a reasonable move.

It may seem odd that a word for ammunition, ordnance, occurs in conjunction with maps, but there is a historical connection. Ordnance maps take their name from the UK Ordnance Survey, which got started in the eighteenth century under the auspices of the British Master-General of the Ordnance. The Master-General was a high-level appointee who looked after, among other things, the military’s artillery and ammunition, its ordnance (also spelled, at one time, “ordinance”). The word “ordnance,” at the time the office was created, had a broader application than it does today – it was anything that had to be set in order for some larger goals to be reached.

The Ordnance Survey produced detailed maps of the UK at various resolutions. The maps were especially favored by cross-country hikers. Other countries have followed suit in the mapping game: in Canada we have our National Topographic Survey maps, in the U.S. they have their United States Geological Survey maps. I seem to recall that on occasion we called the North American maps “ordnance maps,” using the British tag as a generic term.