Durability is when something lasts a long time. The durability of your favorite pair of hiking boots keeps them from wearing out even when you've walked many miles in them.
Use the noun durability to describe the quality of permanence or strength that keeps something working or holds it together. Your parents' thirty year marriage has durability, and your sturdy old car that keeps on running mile after mile also has durability. The Latin root word, durabilis, means "lasting or permanent," and comes from durare, "to last or harden."