Corresponds to the anterior. (Costomediastinal) line of pleural reflection. 2. It is deeply notched in the left lung posterior. to 5th costal cartilage by the pericardium costal cartilage by the pericardium. and extends vertically downwards to form. Lingula.
Generally speaking, a principle is a rule, standard, or belief of one kind or another. As an adjective, principal means âmost importantâ, while a principal is â generally speaking â a person who is most important in a particular organization or group.
Legal Definition of principal. 1  1 : being the main or most important, consequential, or influential their principal place of business the principal obligor. 2  2 : of, relating to, or constituting principal or a principal the principal amount of the loan.