Significant figure and Significant digits

Significant figure noun - Any digit of a number that is known with certainty; any digit of a number beginning with the leftmost non-zero digit and ending with the rightmost non-zero digit (or a zero considered to be the exact value).

Significant digits and significant figure are semantically related. In some cases you can replace phrase "Significant digits" with "Significant figure", this phrases are similar.

Significant figure and significant digits are semantically related. You can use "Significant figure" instead a noun phrase "Significant digits".