There are many families that pass down things through the generations, from father to son, or mother to daughter. These things are called heirlooms.
An heirloom is usually valuable, however it need not always be. It could be financially valuable or it may have sentimental value, which may drive the family to preserve it and pass it down through generations.
The term “heir” means someone who will inherit, while “loom” meant “tool”. Hence an ‘heirloom’ is essentially a tool that is inherited. The term originally referred to property that was passed down, however today heirlooms are usually knickknacks that have some financial but more sentimental value.