A fact known from direct observation.
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.
To provide missing data points by using a mathematical model to extrapolate values that are outside the range of a measuring device.
Witness; evidence; proof of some fact.
Statements made by a witness in court.
In a church service (or religious service), a personal account, such as one's conversion, testimony of faith, or life testimony.
An account of first-hand experience.