WHAT means Dre like in anatomy?

In the context of anatomy, DRE commonly stands for "Digital Rectal Examination." 

A "Digital Rectal Examination" involves the clinician inserting a lubricated, gloved finger into the patient's rectum to manually detect abnormalities, growths, or other medical conditions through direct palpation of the lower gastrointestinal tract, primarily the rectum and prostate gland in males. DRE examinations aid in diagnosing potential medical problems such as hemorrhoids, inflammation, tumors, prostate enlargement, or fecal impaction in the lower part of the large intestine.