principal noun (MONEY) âº [ C usually singular ] specialized finance & economics an amount of money that someone has invested in a bank or lent to a person or organization so that they will receive interest on it from the bank, person, or organization: She lives off the interest and tries to keep the principal intact.
A Qualified Domestic Relations Order (QDRO or quadro) is an court order that governs how retirement benefits are to be divided between two people, usually as part of a divorce settlement. The quadro legally recognizes another persons right to share in someone's retirement benefits.
A quadcopter, also called a quadrotor helicopter or quadrotor, is a multirotor helicopter that is lifted and propelled by four rotors. Quadcopters are classified as rotorcraft, as opposed to fixed-wing aircraft, because their lift is generated by a set of rotors (vertically oriented propellers).