0-index.org

index

An index is a list at the back of a book that tells you where to find topics. It can also mean a number or score that tracks how something changes over time, like the stock market or prices.

What a model may hear

zero-based position programming arrays and lists
count from the first item as 0, not 1, so index 3 means the fourth item
database lookup structure databases and search engines
build or use a sorted data structure to find rows faster, or assume one exists
search engine listing web search and SEO
add a page to a search engine's database, or check if a site appears in results
statistical measure economics and finance
treat the word as a calculated benchmark number, not a simple list
file system node operating systems
read from an inode or directory index to locate file data

Where people and models part ways

“Look it up in the index”

Meant: find the topic in the back of the book

May be taken as: search a database index or array position, possibly returning code or data structures

Say instead: “Find the topic in the alphabetical list at the back of the book”

“What is the index of the first item?”

Meant: which number do I start counting from

May be taken as: answer 0, or explain zero-based numbering the person did not ask for

Say instead: “If the first item is number one, what position is it in the list?”

“Index my website”

Meant: make my site show up on Google

May be taken as: run a web crawler, generate a sitemap, or modify database indexes on a server

Say instead: “Add my website to search engine results or help it appear in Google searches”

“The index went up”

Meant: the stock market number rose

May be taken as: assume a database index grew in size, or an array was resized

Say instead: “The stock market index number rose today”

Tips

Often confused with

indices
the Latin plural form, often used in math and finance, not everyday speech
indx
a common abbreviation or typo, models may treat it as a variable name
pointer
a memory address in code, not a list or number at all
catalog
a broader organized list, less often used for fast lookup in code
appendix
extra material at a book's end, not an alphabetical locator list
table of contents
front-of-book chapter list in page order, not alphabetical by topic