DTR stands for "define the relationship," the conversation where two people decide if they are officially dating. Not concerning, healthy dating vocabulary. Worth knowing as a parent. If your kid uses it constantly, ask them where they first heard it, not to police their speech but to understand which online community they are in. Most slang of this kind moves through TikTok and group chats, so seeing it in your child's vocabulary just means they are plugged into normal teen internet culture.