Dear Word Detective: My roommate from Ohio insists on saying "It's a horse of peas" meaning "It's the same thing, one way or another." After hearing him use this random saying over and over, I finally called him on it and asked him if he didn't mean it was "a horse apiece"? He is adamant about his pea horse (I imagine a green horse consisting entirely of English peas) and won't hear any different. Please enlighten us with your expertise. -- Allison Paige, via the internet.
"Horse of peas"? I'm going to put this one at the very top of a file I keep labeled "Conclusive evidence that Ohio is actually a lost colony of Martians."
In any case, you are correct and your roommate is a victim of a "mondegreen," or a mishearing of a popular phrase or song lyric. The term "mondegreen" was invented in 1954 by the writer Sylvia Wright, who as a child had heard the Scottish ballad ''The Bonny Earl of Murray" and had believed that one stanza went "Ye Highlands and Ye Lowlands, Oh where hae you been?, They hae slay the Earl of Murray, And Lady Mondegreen." It turned out, as Wright later learned, that the line actually ran "They hae slay the Earl of Murray and laid him on the green." Oops, no Lady Mondegreen, but Wright did have a good name for the phenomenon.
"A horse apiece" means, as you supposed, "more or less equal" or "six of one, half dozen of the other." Field researchers for The Dictionary of American Regional English (DARE) first heard "a horse apiece" in 1980, but the phrase is undoubtedly much older. A similar phrase, "horse and horse," dates back to at least 1846.
According to DARE, the logic of "a horse apiece" may come from an old dice game called "horse" in which two players who have each lost a turn are said to be "a horse apiece." Or it may just be a variant of "horse and horse," describing two horses racing neck-and-neck down a racetrack.
I say "a horse apiece" quite frequently. I picked it up from my parents, but my wife has never heard anyone use the expression outside of my family. One day, she searched for more information about the phrase, and came up with the article quoted above. She thought "a horse of peas" was hilarious, and so did I. She even designed a T-shirt for me (available at her CafePress store here) as a Christmas gift. So now I not only have a ready-made blog logo, I've already got merchandise available! Not bad for 10 posts into a new venture.