Obligatory/obligation obligatory"(adjective 1 required by a legal moral, or other rule; compulsory for instance, use of seat belts in cars is now obligatory 2 so customary or routine as to be expected of everyone or on every occasion 3(of a ruling having binding force for instance a sovereign whose laws are obligatory oRiGin late middle english from late Latin obligatorius, from Latin obligat- obliged from the verb obligare, from ob-toward+ligare to bindObligatory/Obligation • “Obligatory” (adjective): 1) required by a legal, moral, or other rule; compulsory: for instance, use of seat belts in cars is now obligatory. • 2) so customary or routine as to be expected of everyone or on every occasion. • 3) (of a ruling) having binding force: for instance, a sovereign whose laws are obligatory. • ORIGIN late Middle English : from late Latin obligatorius, from Latin obligat- ‘obliged,’ from the verb obligare, from ob- ‘toward’ + ligare ‘to bind.’