# Prefix

A **prefix** is an affix that, when added to the beginning of a word, changes its meaning or value. For example, a byte is eight bits of data. However, a megabyte is eight million bits of data because mega is a prefix meaning "one million." With processors, the number of cores is denoted by prefixes. For example, a hexa-core processor has six cores. In computing, a prefix can also be a set of characters at the beginning of a string.

## What are number prefixes?

To prevent confusion, some numbers have prefixes to help identify the type of numbering system. For example, "0x" (zero and x) is used as a prefix to represent a hexadecimal number (e.g., *0xCD* to represent 205 in decimal). Another example is "0b" (zero and b) to represent a binary number. For example, *0b0100* represents 4 in decimal.

## Examples of computer prefixes

The following list contains examples of prefixes related to computers in alphabetical order. Clicking any of the links gives you further information and examples of terms using these prefixes.

Because many of these prefixes are related to measurements, we've added "(measurement)" to all measurement-related prefixes.

- Atto (measurement)
- Centi (measurement)
- Cyber
- Deca (measurement)
- Deci (measurement)
- Deka (measurement)
- Di (measurement)
- E- (electronic)
- Exa (measurement)
- Femto (measurement)
- Giga (measurement)
- Hepta (measurement)
- Hexa (measurement)
- Hecto (measurement)
- ISO
- Kilo (measurement)
- Mega (measurement)
- Mono (measurement)
- Micro (measurement)
- Milli (measurement)
- Nano (measurement)
- Nona (measurement)
- Octa(o) (measurement)
- Penta (measurement)
- Peta (measurement)
- Pico (measurement)
- Pseudo
- Super
- Tele
- Tera (measurement)
- Tetra (measurement)
- Tri (measurement)
- Yocto (measurement)
- Yotta (measurement)
- Zepto (measurement)
- Zetta (measurement)

Use our word and letter search to find words containing any prefix.