An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

The middle term in a → geometric progression. Of two terms, the geometric mean is the square root of their product. For example, the geometric mean of 4 and 9 is ± 6. For a series of n terms, it is expressed as: (a₁.a₂. ... .a_n)^1/n.

→ geometric; → mean.