List of CNC Machine Codes, Terms and Definitions. Some of the codes, terms and definitions might be difference between manufactures for difference type of machine and machine controller.
A-axis = Capability of machining tools moving in circular motion around x-axis
B-axis = Capability of machining tools moving in circular motion around y-axis
C-axis = Capability of machining tools moving in circular motion around z-axis
X-axis = Capability of machine tools moving in the x-axis direction
Y-axis = Capability of machine tools moving in the y-axis direction
Z-axis = Capability of machine tools moving in the z-axis direction
D code = Tool diameter offset number
E code = Selection of work coordinate system. Equivalent to G54 to G59
F code = Feedrate
G code = A CNC program code that determines the type of operation to perform
H code = Tool length offset number
I code = Absolute center of arc in x-axis
J code = Absolute center of arc in y-axis
K code = Absolute center of arc in z-axis
L code = The number of repetition of a cycle
M code = The program code that control overall machine function
N code = Block number
O code = The program number allows you to identify your program with a certain number
P code = Parameter
Q code = Depth of cut parameter in canned drilling cycles
R code = Represent the radius, a return point or a general parameter
S code = Spindle speed
T code = Tool number
U code = Relative axis parallel to x-axis
V code = Relative axis parallel to y-axis
W code = Relative axis parallel to z-axis
X code = Absolute machine tool position on x-axis
Y code = Absolute machine tool position on y-axis
Z code = Absolute machine tool position on z-axis