No, thrush in the mouth in adults is not an STD.
Thrush is a type of yeast infection that can develop in the mouth and throat. It is caused by an overgrowth of the fungus Candida, which is normally found in the mouth and intestines. While thrush can be spread through sexual contact, it is not considered an STD.
Thrush can be caused by a variety of factors, including antibiotics, diabetes, a weakened immune system, and hormonal changes. It is most common in infants and the elderly, but it can occur in adults as well. Symptoms of thrush in adults may include white patches on the tongue, gums, or inner cheeks; redness and soreness in the mouth; difficulty swallowing; and a loss of taste.
Treatment for thrush in adults typically involves antifungal medications, either taken by mouth or applied directly to the affected area. It is important to note that even though thrush is not an STD, it can be passed from person to person, so it is important to practice good hygiene and avoid sharing eating utensils or toothbrushes.