Indexing
Point your index finger at someone, and you’re indicating something about them. In other words, you’re pointing something out with that pointer finger.
The words index and indicate share a common Latin root: indicare, meaning to indicate or point out something. That in- prefix doesn’t mean inward or inside, but instead more like toward. Dicare means to declare something. Put them together and you get a word that means to verbally point at something.
Open up a nonfiction book and you’ll see an index near the end. Indexes help you find things. In this case, you can locate important concepts or names discussed in a book by scrolling down alphabetically, so if you know what you’re looking for, you can find it in the text of the book quickly. This is way better than guessing based on the table of contents.
If you’re indexing, you might be making the index of a book, but that’s probably the way you’re least likely to hear the verb form. Instead of trying to figure out which stocks to buy, an index fund will just buy all of the stocks that are in a particular index like the S&P 500, usually with the same proportions (weighting). This activity is often called indexing in financial markets.
Similarly, wages can be indexed to inflation. This means you would get a cost of living raise when prices rise, at least according to some periodic schedule like once a year.
Whether someone is indexing by organizing a list so you can find things quickly or weighting a fund according to the S&P 500, that verbal index finger is pointing underneath the surface.
Indexing is how arrays and other pointers to data structures are accessed.
Indexing a database can dramatically improve performance.
A database index is a supplementary data structure that improves data retrieval speeds by avoiding full table scans. Think of it like a book's index: instead of reading every page to find a topic, you jump directly to the referenced page number.