---
title: Definitions
slug: gpc/gpc-scripting-definitions
description: The sole purpose of a definition is assign a value to a word and therefore make a script easier for a human to read. They do not use any bytecode space in a script. When a script is compiled the words are changed to their assigned value.
docTags: 
createdAt: 2022-02-05T14:05:03.000Z
---

The sole purpose of a definition is to assign a value to a word and therefore make a script easier for a human to read. They do not use any bytecode space in a script. When a script is compiled the words are changed to their assigned value.

## Syntax

:::BlockQuote
define \<name> = \<value or expression>;
:::

:::CodeblockTabs
GPC

```none
<name>  : The name of the constant
<value or expression> : The value or expression assigned to the constant
```
:::

:::hint{type="info"}
**Info:&#x20;**&#x54;he value of the definition must be possible to compute during compilation - meaning you can use math but not math functions.
:::

Once a word is defined and given a value, that word can be used anywhere in the script where a value is valid, as shown below:

:::CodeblockTabs
GPC

```apex
define my_value = 50;

main {
    
    if(get_val(XB1_LT)) {
       set_val(XB1_RT, my_value);
    }

}
```
:::

If you wish to assign a value to a word and change its value during run-time, you would use a variable instead of a **define**.