The verb aid means to assist: to provide what is needed to achieve a goal. The noun aid refers to a person or thing that provides assistance. An aide (from aide-de-camp) is a person who acts as an assistant.
Examples:
- The United Nations appealed for donations to aid flood victims in Pakistan.
- The United Nations called for nearly $500 million in aid for flood-ravaged Pakistan.
- The retired general arrived on the arm of an aide who steadied him as he walked into the national assembly.
Practice:
(a) An _____ to the majority leader said the legislation would come to the Senate floor by the end of the week.
(b) A secretary was hired to _____ the transition team.
(c) Rain was forecast to continue through the week, slowing _____ and rescue efforts.

