The at sign is the symbol @ that appears on every keyboard, looking like a lowercase “a” wrapped in a curving line. You see it in every email address, sitting between someone's name and their email provider: john@email.com or sarah@school.edu.

Before email existed, the at sign had a much simpler job. For hundreds of years, shopkeepers and merchants used it as shorthand in their account books to mean “at the rate of.” If apples cost 50 cents each, they might write “apples @ 50¢” in their ledgers. The symbol saved time and space when recording prices.

When computer scientist Ray Tomlinson invented email in 1971, he needed a symbol to separate a person's name from their computer location. He chose the @ sign because it was on every keyboard but rarely used in people's names, making it perfect for this new purpose. His choice stuck, and now billions of people use the at sign every day.

On social media, the at sign takes on another role: it tags or mentions specific people. When you write @Maria in a post, you're directing your message to Maria or calling attention to her. This usage has become so common that people sometimes say “at” out loud when giving their email address: “Contact me at john at email dot com.”