sigˌnificant ˈfigure BrE AmE ( also sigˌnificant ˈdigit ) noun [countable] technical
a figure that is part of a number and is known to be correct. Significant figures start with the first figure on the left that is not zero, and end with the last figure on the right that is not zero (unless the zero is known to be correct). So the number 0.0302 has three significant figures.