I had always been of the understanding that the title "Viscount" was held by the heir of a landowning Lord who, once the Lord was deceased, then attained the title of Lord ____, and subsequently the new Lord's heir then became the Viscount.

I have just recently read something in which the title Viscount is used to refer to the landowner itself -- as if it were the senior title. I find myself somewhat confused.

Will someone with greater understanding please explain?

Lin