It’s hyphen time

Add comment July 1st, 2009

‘Tis the season for stories about power usage, which means it’s time for this reminder: There’s a hyphen in “kilowatt-hour.”

This is generally the case for terms that combine two types of measurement: kilowatt-hour (power and time); foot-pound (distance and weight); light-year (speed and time).

By contrast, terms that combine a unit of measure and a simple modifier are generally two words: square mile, cubic centimeter, fluid ounce, liquid quart, dry quart, troy ounce, board foot.

And while I’m on the topic, another reminder about light-year: It’s not a unit of time but of distance — how far light can travel in a year. And at 186,000 miles per second, that’s a fur piece — and I don’t mean a mink coat.