Use the noun locality when you need an official-sounding way to say "area" or "region." For example, you might say, "I am so pleased to finally have a doughnut shop in my locality."
You're most likely to come across the word locality in a news story or business report. It's a formal way to talk about a neighborhood or a section of town. The mayor might make a speech about crime in a particular locality, or the prevalence of potholes in another locality. The word has been in use since the 1700's, from the Latin word localis, "relating to or belonging to a place."