third
The position that comes after second in order or rank.
Third is the position that comes after second in a sequence or ordering. When you finish third in a race, two people crossed the finish line before you. When you're third in line at the water fountain, you have to wait for two classmates ahead of you.
The word works as both an adjective and a noun. You might live on the third floor of an apartment building, or eat a third of a pizza (one of three equal parts). In fractions, one-third (1/3) means you've divided something into three equal parts and taken one of them.
People sometimes use third to describe quality or importance, though this can sound dismissive. If someone calls a restaurant “third-rate,” they mean it's inferior to first- and second-rate options. A “third wheel” describes someone who tags along with two friends who'd rather be alone together.
In music, a third is the interval between two notes that are three steps apart on the scale. Play C and then E on a piano, and you've played a third. In baseball, third base is the last base you touch before heading home. And when lawyers talk about a third party, they mean someone besides the two main people involved in a situation, like a witness to an argument between two friends.