"Δρ." is an abbreviation for "Δόκτωρ," which is the Greek word for "Doctor." It is commonly used as a title for individuals who have earned a doctoral degree, such as a Ph.D. or an M.D. This title signifies a high level of expertise in a specific field of study or profession. In academic and professional contexts, "Δρ." precedes the name of the individual, indicating their qualifications. For example, a person named Maria Papadopoulos who holds a Ph.D. in Biology would be referred to as "Δρ. Μαρία Παπαδοπούλου." This title is respected and recognized in various fields, including medicine, science, and education.