Primary pit field- The area of walls of many cells which is conspicuous in cambium initials and in which one or more pits usually develop.

Pit aperture- the opening from the lumen of cell into a pit cavity in a plant.

Pit membrane- a membrane of a plant pit that consists of a primary wall and middle lamella and that closes the pit externally, also called closing membrane.

Plasmodesmata- They are the microscopic channels which transverse the cell walls of plant cells and some algal cells enabling transport and communication between them.

pit- Pits are the characterists depressions on the cell walls of plant cells.

Simple pits- A pit pairs in which the diameter of pit chamber and diameter of pit aperture are equal.

Bordered pits- A pit pair in which the pit chamber is over arched by cell wall, creating a larger pit chamber and smaller pit aperture.

Pit canal- It is the passage in  bordered pit that is between the cell lumen and pit chambers.

Torus-  it is the thickened central part of the pit membrane in the bordered pits of many gymnosperms , consisting of primary cell wall materials.