Old describes something that has existed for a long time or someone who has lived many years. Your grandfather is old compared to you, an ancient Roman coin is old compared to a quarter, and a 200-year-old oak tree is old compared to the sapling planted last spring.

But old is always relative. A five-year-old computer seems old in the world of technology, while a five-year-old building is brand new. A book from the 1950s might be old to you but not to a historian studying medieval manuscripts. When paleontologists discover dinosaur fossils, they're finding something incredibly old: millions of years old.

The word can also mean former or previous. Your old school is the one you used to attend before you moved. Your old bike is the one you rode before getting a new one. An old friend isn't necessarily elderly; they're someone you've known for a long time.

People also use old to describe things that are worn out or outdated. Those old shoes with holes in them have seen better days. An old joke is one everyone's heard before. Something described as old-fashioned belongs to an earlier time, like writing letters by hand instead of sending emails or texts.