Principal, subst. 1) a capital sum lent on interest: Merch. IV, 1, 26. Merch. IV, 1, 26 Merch. IV, 1, 26 All's I, 1, 161.
2) abettor, accomplice: “what she should shame to know herself but with her most vile p.” Wint. II, 1, 92.
3) employer: “hath your p. made known unto you who I am?” Per. IV, 6, 89. Per. IV, 6, 89
4) a corner-post of a house: “the very --s did seem to rend,” Per. III, 2, 16.