A Bisect is a stamp cut in half with the Post Office’s permission. The best example was during the World War II occupation of Guernsey, when they ran short of 1d stamps; permission was given to cut 2d stamps in half to make two 1d stamps.
A block of four stamps or more, which are all joined together
Booklet Pane or Stamp Book Pane
This is where a sheet or block of stamps is sold within a booklet. It all started in Luxembourg back in 1895, when someone thought booklets would be a handy way of keeping postage stamps safe in your wallet or pocket - with an added bonus that the Post Office could sell advertising space inside. The idea caught on and developed into what’s now a very popular form of collecting: Prestige Stamp booklets.