STD or sexually transmitted disease is a term used to refer to a group of infections that are commonly spread through sexual contact. Some common synonyms for STD include sexually transmitted infections (STIs), venereal diseases, and sexually transmitted illnesses. Many people use these terms interchangeably, but they all essentially refer to the same thing. While STDs can be uncomfortable and painful, they are also highly preventable. Practicing safe sex, getting tested regularly, and using protection can all help to reduce your risk of contracting an STD. It's important to talk openly with your partner and healthcare provider about your sexual health to keep yourself and others safe.