Used to express something formally required or necessary: I must complete the project by this week.

California has enacted legislation formally requiring the separation of the hospital and medical staff.

The expertise of the incumbent is generally expected to include philosophical theology, although the post does not formally require this.

While the government formally requires licensing for both motorcycles and their operators, these rules are largely ignored.

Even if no quid-pro-quo is formally required, the gift creates a social obligation of reciprocity.

Queensland became the last state to formally require the addition of fluoride to public drinking water supplies in December 2008.

Although this Presidency is not formally required to solve the problem, each of the governments should be required to assume its responsibilities.

Here, the infinitive is formally required in both variants:

Essentially, this protocol formally requires states to prohibit the sale of children, child prostitution, and child pornography.

Although not formally required, pseudorotation normally involves displacements along low-energy pathways.