I ran across the term anemoia - nostalgia for a time you never experienced - on the internet and traced it back to this book. The author made up a list of words, or re-purposes existing phrases, for obscure feelings we feel as we age, experience the passage of time, realize how little of it we have left. Besides anemoia I mentioned, one of the words that has made it from the book into the "real-world" is sonder - the realization that each random passerby is living a life as vivid and complex as your own.
While reading I made a list of the words I liked that hit me, so the book is fun and thoughtful, even if your favorite ones never make it beyond the book. And due to the introspective nature of the topic, this book would be better appreciated by older, thoughtful readers, less so by those in the earlier stages of life.
And I have my own term to add: “college degree” as a unit of time, which equals four years. Its use is when you realize an event took place four years ago, which seems so recent, then you think “I could have gotten a college degree since then!” In contrast to your real college degree, which seemingly took forever.