Hey is a casual greeting, like saying “hello” but more relaxed and friendly. When you walk into class and say “Hey!” to your friend, you're acknowledging them in an informal, easygoing way.

The word works best with people you know well: friends, classmates, family members. You probably wouldn't greet your principal or a stranger's grandmother with “Hey” because it might seem too casual or even disrespectful. Context matters.

Hey also works as an attention-getter when you need someone to notice something quickly: “Hey, watch out for that puddle!” or “Hey, look at this!” In this usage, it's like tapping someone on the shoulder with your voice.

The word carries a friendly, sometimes playful tone. When someone texts “hey” instead of writing a formal message, they're keeping things light and conversational. But be careful: saying “Hey!” in a sharp tone can sound annoyed or confrontational, like “Hey! That's my seat!” The same word can feel completely different depending on how you say it.