Facing error in plsql procedure while using if else

I have included a snippet from my plsql procedure. In this I have an if else if lock.I am doing a string comparison in IF which is not giving an error and another string comparison in ELSE IF which is highlighted in red and giving an error.
I am unable to understand why.

IF x='new' THEN
   --sql statement

ELSEIF x='old' THEN
   --sql statement
END IF;

>Solution :

Syntax for else if is elsif not elseif, without the ‘e’.