Two' is a three letter word that is used to describe the number of people needed to operate a seesaw. A seesaw is a playground equipment consisting of a board balanced on a fulcrum, allowing TWO people to sit at either end and take turns going up and down. It is also known as a teeter-totter. TWO people are needed to make the seesaw work, as one person sitting on one end will not be able to move it.