g-force (also G-force, g-loa) is a measurement of an object's acceleration expressed in gs. It may also informally refer to the reaction force resulting from an acceleration, with the causing acceleration expressed in gs. The g (pronounced /ˈdʒiː/) is a non-SI unit equal to the nominal acceleration due to gravity on Earth at sea level, defined as 9.80665 m/s2 (32.174 ft/s2). More precisely, g-force measures the net effect of the acceleration that an object actually experiences and the acceleration that gravity is trying to impart to it, as explained further below. The symbol g is properly written in lowercase and italic, to distinguish it from the symbol G, the gravitational constant, which is always written in uppercase; and from g, the symbol for gram, which is not italicised.