The term 'short-lived things' can be summarized by the word 'ephemera', which is an 8-letter word. Ephemera refers to objects or events that are transitory and quickly pass away, such as a passing fad or trend. It is often used to describe items of collectible memorabilia, such as postcards, posters, tickets, and other printed materials. These items are usually produced in limited quantities and have a short lifespan, making them highly sought after by collectors.