Breath (pronounced "brehth," with a short e) is a noun derived from the Old English noun bræð (which means “odor, scent, stink, exhalation,” or “vapor”) that refers to “air taken into the lungs and then let out.”
Claire and Sherry ran through the police station parking lot and into the station sub-level hallway, where Claire paused to let the young girl catch her breath.
Breathe (pronounced "breeth," with a long e) is a present-tense conjugation of the verb to breathe (also derived from bræð), which means “to take (air) into the lungs and let it out again.”
As she and Leon walked past Luis’s body, Ashley carefully eyed Luis’s nostrils and chest in hopes of seeing him breathe. He didn’t.
An easy way to remember the difference between these two is the same thing that makes them often difficult to distinguish from each other: the e on the end of the conjugated verb. Just remember: the noun will never have a second e, but the verb will always have one (as well as an s or d sometimes, depending on its tense and subject) unless it is in its present participle form, breathing.
Because living beings cannot last long without breathing, the act has become tied to—even symbolic of—having life. This symbolism is why writers will sometimes include a remark about breathing either before or after a near-fatal encounter.
“Look, Chris, I’m sorry about leaving you to deal with that monster all by yourself,” said Jessica. “You’re not going to stay pissed and ignore me forever, are you?”
"Don’t worry about it,” he said a little more gruffly than he meant to. “We’re both still breathing, and that’s what matters.”
The pace of someone’s breath can indicate the emotional state that he or she is in, which is why someone who is under high emotional stress often feels or is described as breathless (meaning that he or she is so emotionally stressed that he or she cannot breathe properly).
Jill put down the Umbrella memo with Captain Wesker’s name on it, feeling breathless. Their own leader was in league with the company, and he had handed her and the other members of S.T.A.R.S. over as guinea pigs for its experiments!
Likewise, the regaining of breath can indicate that the person is in a more stable condition and no longer emotionally stressed. Two common phrases that express this decline in emotional stress are to breathe a sigh of relief and to take a breather (to take a break during which one may regain breath and/or relax).
Something poked Rebecca in the shoulder. Gasping, she whirled around and found only a statue of a blindfolded man with outstretched hands behind her. She breathed a sigh of relief.
Leon shouldered open the door. On the other side was a small storeroom full of shelves of files and medical supplies. “No zombies in here,” he said, glancing back at Ada with a smile. “Let’s take a breather before we move on, okay?”
I hope that you enjoyed this quick breather, and remember: the noun will never have a second e, but the verb will always have one unless it’s in its present participle form!
Webster’s New World Dictionary, Third College Edition