The following are the main criteria that a domain has to be:

For a .eg domain name use only letters, numbers, or hyphen “-“.
A domain has to start with a digit and end with a digit.
Hyphens cannot start or end your domain. A .eg domain can not contain hyphens in the third and fourth positions (e.g. www.ab- -cd.eg).
You can’t use symbols (such as ‘ + . , | ! ” £ $ % & / ( ) = ? ^ * ç ° § ; : _ > ] [ @ ), or spaces or stressed vowels (such as à, é, ò, í).
The .eg web name length may vary, from 3 to 22 types.