Meaning of PRINCIPAL in English
1》 first in order of importance; main.
2》 denoting an original sum of money invested or lent.
1》 the most important or senior person in an organization or group.
↘the head of a school or college.
↘(in certain professions) a fully qualified practitioner.
2》 a sum of money lent or invested, on which interest is paid.
3》 a person for whom another acts as an agent or representative.
↘ Law a person directly responsible for a crime.
4》 a main rafter supporting purlins.
5》 an organ stop sounding a set of pipes typically an octave above the diapason.
ME: via OFr. from L. ~is 'first, original', from princeps , princip- 'first, chief'.
On the confusion of ~ and principle , see usage at principle .
Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004