|≈||approximately equal to|
|digits||indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …)|
A barn (symbol: b) is a unit of area equal to 10−28 m2 (100 fm2). Originally used in nuclear physics for expressing the cross sectional area of nuclei and nuclear reactions, today it is also used in all fields of high-energy physics to express the cross sections of any scattering process, and is best understood as a measure of the probability of interaction between small particles.
The stremma (pl. stremmata; Greek: στρέμμα, strémma) is a Greek unit of land area now equal to precisely 1,000 square meters. It is also known as the royal stremma to distinguish it from earlier forms of the unit.