1) The smallest distinguishable increment into which a quantity can be devised (e.g., position or shaft speed). 2) The degree to which nearly equal values of a quantity can be discriminated. 3) For rotary encoders, it is the number of unique electrically identified positions occurring in 360 degrees of input shaft rotation. 4) For D/A or A/D conversion, may be expressed as the number of bits in the digital value that corresponds to a full-scale analogue value.