Originally, the words that described bolts of light from the sky and making something less dark were the same. Today, we have lightning and lightening. Here's a memory trick to help you remember the different modern spellings.
The word lightning is quite old. The first citation in Oxford English Dictionary that uses lightning as a noun to describe light from the sky is from 1377. Back then, in Middle English, spelling was different from our Modern English spelling. Lightning was spelled with a y and a letter we don’t even use today called a yogh that kind of looks like the number 3 and was eventually replaced with our current letters gh.
Today, there are two forms of the word lightning, and people often get confused about their spellings.
Dictionaries say that long ago the two words were spelled the same. They both come from the word light, which goes back even further, all the way to Old English before the year 900. But today, the lightning we’ve been talking about—the bolt from the sky—doesn’t have an e. The other kind of lightening—what people do when they get their hair bleached, for example—is spelled with an e.
Lightning, without an e, can also be a metaphor for something that’s fast: games, game shows, and even TV shows often have a lightning round—one of the earliest game shows to have a “Lightning Round” was in the show Password in 1961—and Lightning McQueen was the name of one of the racers in the movie Cars.
One of my favorite quotations about lightning come from Mark Twain.
He said, “The difference between the right word and the almost right word is a really large matter—it’s the difference between lightning and a lightning bug.”
Get the right word, and remember to spell lightning properly. If you’re writing about someone lightening hair, it’s spelled with an e; but if you’re writing about Percy Jackson and the Olympians: The Lightning Thief, it’s spelled without the e. My agent, Laurie Abkemeier came up with a good memory trick. She said, “Just think of a lightning bolt zapping the e out of the word.”