A seemingly self-evident or necessary truth which is based on assumption; a principle or proposition which cannot actually be proved or disproved.
A fundamental assumption that serves as a basis for deduction of theorems; a postulate (sometimes distinguished from postulates as being universally applicable, whereas postulates are particular to a certain science or context).
An established principle in some artistic practice or science that is universally received.
A premise from which conclusions are drawn.
A floating reference point, or SLDMB, used to evaluate surface currents in a body of water. Often employed by coastal search and rescue.
A fixed reference point or set of reference points which precisely define a system of measurement or a coordinate system.
A fact known from direct observation.
To provide missing data points by using a mathematical model to extrapolate values that are outside the range of a measuring device.