Basically he intended 'type' as not 'datatype' as in 'dwSomething' (for double word) but the purpose of the variable. For example, if you're using an integer variable to store the length of some entity, you would name it something like 'lenSomething' as opposed to 'dwSomething'.

Storing the type of the variable makes little sense as in most cases it is only a quick grep away.