Unknown. First recorded in 1780 in the sea journal of an Englishman. There are two respectable-sounding theories as to its origin, although there is no evidence for either:
The term apple-pie bed originates from around the same period, which gives a bit more credibility to the "folded linen" origin.
- (colloquial, dated) A neat and tidy arrangement or organization
- Partridge, Dictionary of Slang, 7th Ed.
- "Apple-pie order" in Michael Quinion, Ballyhoo, Buckaroo, and Spuds, 2004.