Glossary

A Aspect ratio Aspect ratio is the proportion of an image's width to its height, such as… B Basal Metabolic Rate (BMR) BMR is the energy your body uses at complete rest to keep you alive. B Base32 Base32 encodes data using 32 characters, the letters A-Z and digits 2-7, with =… B Base58 Base58 is a binary-to-text encoding that drops look-alike characters (0, O, I and l)… B Base64 Base64 is an encoding that represents binary data using 64 printable characters (A-Z, a-z,… B Bit and byte A bit is a single 0 or 1. A byte is 8 bits. B Body Mass Index (BMI) BMI is weight in kilograms divided by height in metres squared. B Box shadow The CSS box-shadow property draws a shadow around an element using offsets, blur, spread… C Caesar cipher A Caesar cipher replaces each letter with the one a fixed number of places… C CIDR notation CIDR notation writes an address and the length of its network prefix, such as… C Contrast ratio (WCAG) Contrast ratio compares the relative luminance of two colors, from 1:1 (identical) to 21:1… C CSS gradient A CSS gradient is a background image generated by the browser that blends two… C CSV CSV (comma-separated values) is a plain-text format where each line is a record and… E EXIF data EXIF is metadata embedded in photos, such as camera model, capture date and sometimes… F Favicon A favicon is the small icon shown in browser tabs and bookmarks for a… G GCF and LCM The greatest common factor is the largest number that divides two numbers exactly. The… G GPA Grade point average is the average of grade points weighted by credit hours, usually… H Hexadecimal Hexadecimal is a base-16 number system using digits 0-9 and letters A-F. H HSL HSL describes a color by hue (an angle on the color wheel), saturation and… H HTML entity An HTML entity is a code such as < or & that represents a… I IPv4 address An IPv4 address is a 32-bit number written as four decimal numbers from 0… J JSON JSON (JavaScript Object Notation) is a lightweight text format for structured data made of… L Lossy and lossless compression Lossless compression shrinks a file without losing any data. Lossy compression discards some detail… M Meta description A meta description is an HTML tag that summarizes a page. Search engines may… M Minification Minification removes characters that are not needed for a machine to read a file,… O Open Graph Open Graph is a set of meta tags that tell social platforms the title,… R RGB RGB describes a color by the amounts of red, green and blue light, each… r robots.txt robots.txt is a text file at the root of a site that tells crawlers… S Scientific notation Scientific notation writes a number as a value between 1 and 10 multiplied by… S SERP A SERP, or search engine results page, is the page a search engine shows… S Standard deviation Standard deviation measures how spread out numbers are around their mean. S Structured data (JSON-LD) JSON-LD is a format for adding structured data to a page so search engines… T Token (LLM) A token is a chunk of text, often part of a word, that a… T Total Daily Energy Expenditure (TDEE) TDEE is the total calories you burn in a day: your BMR plus the… U URL encoding (percent-encoding) URL encoding replaces characters that are not safe in a URL with a percent… U URL slug A slug is the readable part of a URL that identifies a page, for… W Well-formed XML XML is well-formed when it follows the basic syntax rules: a single root element,…