Grammar Girl here. I'm Inion Fogarty, your friendly guide to the English language. Today,

we're going to talk about dime idioms and syllable acronyms. A grammar-palusian named David sent me down a shiny little rabbit hole,

or maybe I should say a coin slot with this one,

he wrote in about the idiom to turn on a dime, or sometimes to turn on a dime and give you back

change. David wrote, these days it's used mostly in reference to someone rapidly changing their

mind, often to diametrically

oppose what they previously said. In origin, it seems to have been 1930s powerboat advertising

to emphasize the maneuverability of high-powered boats, and it later got picked up by car

enthusiasts. The current usage seems more recent, 21st century. At least

that's what turns up in Google and Graham searches. So thanks to David, today we're talking

about dime idioms, some that have been around for more than a century, others that still

jingle in modern speech, and will even bust a little assumption you might have heard about

the word dime itself. Let's start with David's question and go back even farther than those

sleek 1930s powerboats, because although the powerboat ad hypothesis is pretty widespread,

it turns out that in American English, turn on a dime was already kicking around by the

1890s. And before that, horse trainers were bragging that their mounts could turn on a five-cent

piece. Across the Atlantic, British riders had a similar turn of phrase in the late 1800s,

turn on a six-pence, usually reserved for polo

ponies or cavalry horses that could spin sharply in a tight space. The image was the same,

a creature pivoting on the space of a tiny coin. And by the time motorboats and cars came along,

the metaphor was ready-made for anything with impressive maneuverability.

Those 1930s powerboat ads David mentioned certainly helped cement the phrase in the public mind, though,

...