WHAT IS THE MEANING OF" CRAB SHOT" IN FILM DIRECTION?

PLEASE EXPLAIN ABOUT THE" CRAB SHOT" IN film direction?HOW CAN IT MAKE ?

Here’s something like a glossary of filming terms:

http://www.aber.ac.uk/media/Documents/short/gramtv.html

You can find ‘crab’ under Camera Techniques: Movement (about a third of the page down); there are example pictures which help with differentiating one technique from another.