Instructions per second (IPS) is a measure of a computer's processor speed.
A million instructions per second (MIPS) is an older, obsolete measure of a computer's speed and power.
The term is commonly used in association with a Metric prefix (K, M, G, P, or E) to form kilo instructions per second (KIPS), million instructions per second (MIPS), and billion instructions per second (GIPS) and so on.