moment of inertia, I, J

https://dx.doi.org/10.1351/goldbook.M04006
Of a body about an axis is the sum of the products of its mass elements and the squares of their distances to the axis. Principal moments of inertia of a molecule are chosen so that I A ≤ I B ≤ I C.
Source:
PAC, 1996, 68, 957 (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 983