Lowercase Letter

Lowercase is the description given to small letters, as opposed to capital letters. For example, the word yes is in all lowercase letters, whereas the word YES is in all uppercase letters.

They are given the name lowercase because of how early publishers stored movable type pieces for use with printing presses. In these settings, a publisher would typically have large wooden cases with smaller compartments that contained individual letters, numbers, and symbols in multiple fonts. Capital letters were usually stored in a higher (or upper) case, and small letters were usually stored below in a lower case. As printing presses became more of a commodity, the terms uppercase and lowercase became part of the vernacular to distinguish the different types of letters.

When to use lowercase letters

Lowercase letters have particular significance in a range of use cases.


In most writing systems, the majority of words are written in lowercase. Common exceptions to this would be the first word of a sentence or prepositions, articles, and conjunctions in a title (unless they are the first or last words). Common words—as opposed to proper nouns—are usually written in lowercase. Additionally, abbreviations for units of measurement are written in lowercase except for liter (L) and those derived from a person’s name, like Watt (W) or Hertz (Hz).


Some programming languages are case sensitive, so lowercase letters are used to distinguish different identifiers. For example, “Print” and “print” would be considered two separate identifiers that create different outcomes. This presents a risk for errors in the code, so programmers must be extremely careful when writing code to avoid using a capital letter that should be lowercase or vice-versa.

Some high-level, case-sensitive languages include:

Password security

Many applications and platforms require a mix of lowercase and uppercase letters in addition to other characters when creating a user password. The variety of letters expands the number of variables that could be used, thereby making the password harder to crack. Alongside numbers, capital letters, and symbols, lowercase letters are a main component of strong password health and security.

Database software

Some databases, like Microsoft’s MySQL, can be configured to differentiate between uppercase and lowercase letters when collating a set of text values. This means the database will order capital letters separately from lowercase letters instead of consolidating them to be read as the same value. This can be done across the whole database or limited to a single text column or query, depending on the user’s needs.

UPDATED: This article has been updated April 2021 by Kaiti Norton


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