a murderer (especially one who kills a prominent political figure) who kills by a treacherous surprise attack and often is hired to do the deed; "his assassins were hunted down like animals"; "assassinators of kings and emperors"
a member of a secret order of Muslims (founded in the 12th century) who terrorized and killed Christian Crusaders
a method of surveying; the area is divided into triangles and the length of one side and its angles with the other two are measured, then the lengths of the other sides can be calculated
a trigonometric method of determining the position of a fixed point from the angles to it from two fixed points a known distance apart; useful in navigation