LMB stands for Left Mouse Button, which is an essential component of computer input devices such as a mouse or trackpad. It is located on the left side of a standard computer keyboard and is operated by the index finger. The LMB has various functions, including left-clicking, selecting and dragging items, and opening context menus. It is used for clicking, dragging, and often opening files.

When following instructions for mouse-clicks and key presses, LMB means click or press the left-mouse button. In some software, such as Blender, LMB can be used in combination with other keys, such as Ctrl, to perform specific actions.

To use the LMB efficiently, users can follow tips such as practicing proper clicking techniques and utilizing shortcuts.