Constants are keys that contain a value, much like how a variable does.

However, the first notable exception is that the value of Constant cannot be changed once set.

Additionally, to define a constant, the syntax is "define('NAME', value)"

Lastly, to call a Constant in an echo, it cannot be included in quotation marks. Instead, they must be concatenated into the string.


My name is Thomas and I am going to school at UWM

Written as: "My name is " . FIRST_NAME . " and I am going to school at " . SCHOOL