Dot

Dot is a small round mark used in writing and printing. In American English it is typically called a period, while in British English it is called a full stop. It serves to end a sentence, and three dots in a row form an ellipsis, indicating a pause or unfinished thought.

In numbers, the dot functions as a decimal point in many locales, as in 3.14. In some European countries, the dot is used as a thousands separator (for example, 1.234) while the decimal separator may be a comma. Usage varies by region and formatting standards.

In computing and online writing, a dot is used to separate elements in file names and domain names, such as report.pdf and subdomain.example.com. In Unix-like systems, a leading dot on a file name (for example, .bashrc) indicates a hidden file. In programming, the dot operator often denotes member access, as in object.property or object.method().

In mathematics and physics, the term dot appears in several conventions. A centered dot can indicate multiplication in some mathematical notations. A dot over a variable (a·) commonly denotes a time derivative in physics (as in ẋ for dx/dt). The dot notation is also used in various scientific and engineering contexts to indicate related operations or relationships.

Overall, the dot serves multiple, sometimes overlapping roles across language, mathematics, and technology, linked primarily by its simple, circular glyph.