Question: What is "stigmata"? What was especially unique about St Francis of Assisi's stigmata?
Answer: Stigmata is a term used by members of the Christian faith to describe bodily marks, sores, or sensations of pain in locations corresponding to the crucifixion wounds of Jesus Christ, such as the hands, wrists, and feet.
St. Francis of Assisi is the first recorded stigmatic in Christian history. His stigmata had figures of nails in his hands and feet.
Read more:
http://www.catholic.org/saints/stigmata/
http://www.franciscanfriarstor.com/archive/stfrancis/stf_stigmata_of_st_francis.htm