A palindrome is a sentence, phrase, name, word or number series where the letters or numbers are in the same sequence when read forward or backwards. Some examples would be: 2002 racecar radar,...
Because it doesn't read the same way backwards and forwards. A word does not need to be an example of its definition. Often the sound of the word confuses the general public of the meaning, such as...
The number '4' can be considered a palindrome because it is read the same whether forward or backward. It can become another palindrome when it is considered as 2x2.