The word is Dummy. Somehow the Y has not shown.
These index cards etc are available because the Western Front Association saved them from being destroyed some years ago. The WFA volunteers have worked hard to make them available now online (via Ancestry Fold3) but prior to this would have conducted time consuming searches of the millions of cards and ledgers.
The WFA website has quite a few items regarding the cards/ledgers including a section dealing with 'Understanding the Ledger Indexing' (scroll down to it). The answer to your queries will undoubtedly be there.
https://www.westernfrontassociation.com/ancestry-pension-records/Edit. I have now scrolled down to the bottom of the list of articles and see there were 8,000,000 items all told. A large lorry load.
