Maps and surveying

Le piquet d’arpentage costs an English reader nothing to learn, because the word has already been borrowed. Le piquet is a small pointed thing driven into the ground — it is built on piquer, to prick — and that is exactly what a surveyor plants at the corner of a plot. English took it as « picket » and then let it travel. The literal stake survives in « picket fence », a fence of pointed uprights, and in picketing a horse, tethering it to a peg. From there it went to the army, where a picket was a small guard posted out in front of the main body, set at intervals the way stakes are; and from the army it reached the strike, so that a « picket line » today is a row of people and not of stakes at all. French made the same last step independently and says un piquet de grève. It kept one sense we never borrowed: être au piquet is to be stood in the corner at school, planted there like a post.