Pica-speak

Here in The Guardian Online is a most interesting story about a disorder that causes people to consume, quite literally, anything they can stuff into their mouths: toilet paper, cigarette butts, sand, what have you. This condition is called "pica", and of course I had to wonder where the name came from and if there could be any relationship between it and the unit of measure also known as the pica.*

The unit of measure (which is one sixth of an inch, by the way) is, according to Answers.com, from Mediaeval Latin "pica", 'list of church services". It then adds, "perhaps from the typeface used to print it", but the OED notes that "no edition of pica...in 'pica' type appears to be known".

The other pica, the illness, derives, amazingly, from the same source as "magpie", because such birds are great and indiscriminate eaters; the New Latin word for the bird is "pica".

Both words, since you were probably wondering, are pronounced the same, and since "magpie" is the source of one of them, it will not surprise you to learn that that pronunciation is "PIE-ka" and not "PEE-ka".** The similar-sounding "pike" has a number of meanings and correspondingly a number of derivations, none of which has anything to do with "pica" (most of them ultimately derive from French "piquer", "to prick").


* It turns out there's a third "pica", as well: it's an old spelling of "pika", a preposterously cute, hamsterish animal that's actually not a rodent but a lagomorph, the family of animals which also includes rabbits and hares--as well it might, because the word "lagomorph" is from the Greek for "hare-shaped".

** The obviously unrelated prefix "pico-", "one trillionth", is pronounced "PEE-ko". Or "PIE-ko": your choice, for a change.