A letter is a symbol that represents a sound in written language. The English alphabet has 26 letters, from A to Z, and we combine these letters to form words. When you write “cat,” you're using three letters: c, a, and t. Each letter corresponds to a sound, and together they create the word you want to express.

Letters can be uppercase (capital) like A or lowercase (small) like a. We use capitals at the beginning of sentences, for names, and for emphasis. The same letter can represent different sounds in different words: the a in “cat” sounds different from the a in “cake.”

The word also means a written message sent from one person to another. Before email and texting, people communicated over distances by writing letters on paper and mailing them. A letter might contain news, questions, thoughts, or feelings. Famous historical letters, like those between John Adams and his wife Abigail, give us windows into the past. Even today, receiving a handwritten letter in the mail can feel more personal and thoughtful than a quick text message.

When something follows rules exactly, we say it follows them “to the letter,” meaning precisely and completely, just as letters on a page appear in a specific, unchangeable order.