The world of sexual health is filled with countless acronyms: STD, STI, HPV, HIV, HSV — and those are just the common ones. STD (sexually transmitted disease) and STI (sexually transmitted infection) are two of the abbreviations that can be the most confusing: are they synonyms that can be used interchangeably? If so, why can’t the medical community just agree on one? Or do the two refer to entirely different concepts?

The key difference between the acronyms lies in the terms “infection” and “disease.” As the American Sexual Health Association explains, disease “suggests a clear medical problem, usually some obvious signs or symptoms.” Those symptoms could include things like warts, strange smelling or colored discharge, a sore throat, or a fever.

Often times, an individual who has contracted infections like chlamydia, gonorrhea, herpes, or human papillomavirus (HPV) might not have any symptoms at all — or they’re so mild they go unnoticed. In this case, the definition of “disease” does not apply.

For this reason, many professionals and organizations are increasingly using STI instead of STD, partially because the term is more inclusive. As the University of Maryland Health Center puts it, “The term STI is broader and more encompassing because some infections may not cause any symptoms. So that’s why you may hear people say ‘STIs’ — it’s technically more accurate and also reminds people that there are often no symptoms so it’s important to get tested.”

According to the Centers for Disease Control and Prevention, STIs are passed from one person to another through skin-to-skin contact or the exchange of bodily fluids. This can include intimate physical contact like heavy petting and sexual activity like vaginal, oral, and anal sex. STIs are extremely common — the CDC estimates 20 million new infections occur every year in the United States.

Some frequently diagnosed STIs include HPV, bacterial vaginosis (BV), chlamydia, gonorrhea, trichomoniasis, herpes, syphilis, and HIV. Many of these are easily recognized with certain symptoms, like foul-smelling discharge, chills, or genital warts. However, as explained above, they don’t always cause symptoms, so it is possible to be infected and not know it. This is why it it’s so important to get tested if you’re sexually active.

While abstinence is the only sure-fire way to prevent STIs, you can lower your risk by using condoms the right way every time. Talk to your partner about their sexual history, the last time they were tested, what they were tested for, and if they currently have any infections.

If you do get diagnosed, don’t freak: again, they’re very prevalent, and you’re definitely not alone. All STIs can be treated and managed, and many are curable. Be sure to talk honestly with any future sexual partners about your STI status.

So, which word should you use? As is stands, both terms are considered accurate in the medical community and there’s not a consensus on which should be used. The CDC and Planned Parenthood primarily use the term “STD” on their websites, while ASHA has stated that it will begin using both “STD” and “STI” on their website and in published documents.

Dr. H. Hunter Handsfield, Professor Emeritus at Washington University Center for AIDS and STD writes, “Those who prefer either term should use it freely, with neither defensiveness nor pride in either one.”

English Taylor is a San Francisco-based women’s health and wellness writer and birth doula. Her work has been featured in The Atlantic, Healthline, Refinery29, NYLON, and Modern Fertility. Follow English and her work at https://medium.com/@englishtaylor or on Instagram at @englishtaylor.