I thought that 'serving' was when a covering of twine was added to, perhaps, a galvanised shroud
. It would then be treated with tar to make it waterproof. So a serving is a protective covering, a whipping specifically protects a rope's end and a seizing secures something. It might be used around a thimble in a halyard
, for instance.
But there aren't many strict definitions in nautical terms, especially taking language differences into account.