A variable's name might be short (like x and y) or longer (like age, car name, or total volume).

PHP variable rules:

• A variable starts with the dollar sign or a letter must come first in a variable name.
• No number may begin a variable name.
• Only underscores (A-z, 0-9, and _) and alphanumeric characters are permitted in variable names.
• The capitalization of variable names ($age and$AGE are two distinct variables)

<?php
     $txt = "1cademy.com";
     echo "I love $txt!";
?>