ASCII 83 — S

The uppercase letter S (ASCII code 83) is the nineteenth letter of the modern Latin alphabet, traced back to the Phoenician shin (meaning tooth) through Greek sigma. In English text, the letter s appears with a frequency of approximately 6.3%, ranking as the 7th most common letter. S is the most common letter at the start of English words and forms plurals, possessives, and third-person singular verb conjugations as a grammatical suffix.

The 26 uppercase Latin letters span ASCII codes 65 through 90, forming the capital letter block of the character set. Their placement exactly 32 code positions before the corresponding lowercase letters (97–122) was a deliberate engineering decision enabling case conversion through toggling a single bit. Uppercase letters are essential for proper nouns, sentence openings, acronyms, and programming constants. Early computing systems often supported only uppercase characters, making ASCII's inclusion of both cases a forward-looking design choice.

In the ASCII encoding table, Uppercase Letter S is assigned code point 83 in decimal (0x53 hexadecimal, 123 octal, 01010011 binary). The 7-bit ASCII standard, first published in 1963 by the American Standards Association, defines exactly 128 characters that remain the foundation of text encoding systems worldwide. UTF-8, the dominant encoding on the modern web, is fully backward compatible with ASCII — every ASCII character is encoded as the identical single byte in UTF-8, guaranteeing that Uppercase Letter S works reliably across all operating systems, programming languages, and internet protocols.