Another word for facultative

By the latest enactments (one dating from 1905) 2500 citizens can claim a vote ("facultative referendum") as to any legislative project, or can exercise the "right of initiative" as to any such project or as to the revision of the cantonal constitution.

The provisions of neither convention are obligatory, but merely " facultative," amounting only to recommendations.

In many cases the colour-production is dependent on certain definite conditions - temperature, presence of oxygen, nature of the food-medium, &c. Ewart's important discovery that some of these lipochrome pigments occlude oxygen, while others do not, may have bearings on the facultative anaerobism of these organisms.

(a) The division into periodical and occasional is important in Hindu and other higher religions, and the sutras constantly draw the distinction; the former class is obligatory, the latter facultative.