The next time you write one of these words, you may want to back up and see if you’ve got it right. Knowing which part of speech you’re using will prove helpful.
“Backup” as a single a word with no space or hyphen can be used either as an adjective (When Johnson got knocked out, the coach put in his backup quarterback.) or as a noun (Noticing that the license plate matched that of a stolen vehicle, the policeman called for backup.).
“Back up” as two words with a space is a verb meaning to go in reverse (“Stop and back up, I think someone was in the alley,” the deputy said to his partner.).
Sometimes “back-up” with a hyphen appears as a replacement for “backup.” The hyphen is unnecessary, though, so back up and go with a single word.
______________
My name is Rob Bignell. I’m an affordable, professional editor who runs Inventing Reality Editing Service, which meets the manuscript needs of writers both new and published. I also offer a variety of self-publishing services. During the past decade, I’ve helped more than 300 novelists and nonfiction authors obtain their publishing dreams at reasonable prices. I’m also the author of the 7 Minutes a Day… writing guidebooks, four nonfiction hiking guidebook series, and the literary novel Windmill. Several of my short stories in the literary and science fiction genres also have been published.