Don't mind at all Jackie,

The MacGuffin
A plot device used to motivate a story. Sometimes in Miss Marple Mysteries there will be a quick cutaway of a necklace or painting. More often than not the shot was added to lead or insinuate something. Or sometimes it's just a red herring. Wanda, in a fish called Wanda was a MacGuffin.
(not to be confused with an egg MacGuffin)

Montage
An editing technique which as the name suggests is a quick series of shots linked together to give more of an allusion to something like time passing or the old 'life flashing before my eyes trick'.

B roll
To dissolve or mix between Two shots before the advent of computers it was necessary to copy one of the Two shots onto another tape or 'B' Roll. Then you cou play both tapes simultaneously and at the appropriate time dissolve between your 'A' and 'B' rolls.

A Split
refers to a split edit where the video from one shot is used under the audio from another shot there are lots of variations of split editing.

The Fourth wall
Is an imaginary wall Whenever you watch a sitcom like That Seventies Show for instance we, the viewer, are in the place of an imaginary wall looking in.