What is meant by the term 'axilla'?

The term 'axilla' refers specifically to the armpit, which is the area located beneath the junction of the arm and shoulder. This anatomical region is important because it contains various structures, including lymph nodes, blood vessels, and nerves. Understanding the axilla is essential in medical fields, as it is involved in various physiological functions and can be an area of interest during physical exams and surgical procedures. The other options refer to different anatomical regions which do not correspond to the definition of 'axilla'; thus, they are not correct in this context.