What is the meaning of "six-three" in this excerpt from a New York Times article?
“Turn around,” Mr. Florence, in an interview last year, recalled being told by jail officials. “Squat and cough. Spread your cheeks.” “I consider myself a man’s man,” said Mr. Florence, a finance executive for a car dealership. “Six-three. Big guy. It was humiliating. It made me feel less than a man.”
I could not find on Google nor Urban dictionary.