Cubic Inch
A cubic inch is an imperial unit of volume equal to the volume of a cube with edges one inch long, or approximately 16.39 milliliters. It is used in the United States for measuring engine displacement and small volumes.
History
The cubic inch has been used as a unit of volume for centuries in English-speaking countries. In the automotive industry, American muscle car engines are often described by their displacement in cubic inches (e.g., a 350 cubic inch V8). The US gallon is defined as exactly 231 cubic inches.