Character encoding

A system that maps text characters to numbers or byte sequences so computers can store, process, and exchange text. It defines how digital data corresponds to written symbols.

Unicode: A universal standard assigning code points to characters used by writing systems, symbols, and emoji. It supplies the shared character repertoire that modern encodings represent.
Character: An abstract unit of written language, such as a letter, digit, punctuation mark, or symbol. Encodings represent abstract characters rather than their visual appearance.
Text file: A file containing data intended to represent text, commonly stored as encoded bytes. Its byte content can only be interpreted correctly with the right encoding.
Character set: A defined collection of characters, often paired with numerical identifiers for them. A character set specifies which characters exist; an encoding specifies their representation.
UTF-8: A variable-width Unicode encoding that represents each code point with one to four bytes. Its byte patterns encode Unicode while preserving ASCII compatibility.
Code point: A numerical value assigned to a character or other unit in a coded character set. Encodings turn code points into sequences of bytes or code units.
HTTP: An application-layer protocol for transferring resources between clients and servers. HTTP metadata can identify the encoding used for transferred text.
Collation: Rules for comparing and ordering text according to linguistic or application-specific conventions. Collation determines text order, not how characters are stored as bytes.
UTF-16: A Unicode encoding that represents code points using one or two 16-bit code units. It illustrates how a character encoding can use fixed-size units but variable-length sequences.
Byte: A unit of digital information consisting of eight bits in most modern computing systems. Text files commonly store encoded characters as bytes.

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