The collective word is 'OUR', which is a three-letter pronoun used to refer to a group of people. It is often used to refer to a group of people who are united by a common purpose or identity, such as a family, a team, or a nation. It can also be used to refer to a group of people who share a common interest or goal. The collective word 'OUR' is often used to emphasize the sense of unity and belonging that comes from being part of a larger group.