The cross-sections of the core and cladding are assumed to a first approximation to be elliptical. Quantitatively, the ovality of either the core or cladding is expressed as , where a is the length of the major axis and b is the length of the minor axis. The dimensionless quantity so obtained may be multiplied by 100 to express ovality as a percentage. Alternatively, ovality of the core or cladding may be specified by a tolerance field consisting of two concentric circles, within which the cross section boundaries must lie.
In measurements, ovality is the amount of out-of-roundness of a hole or cylindrical part in the typical form of an oval.
In computational chemistry, especially in QSAR studies, ovality refers to, a measure of how the shape of a molecule approaches a sphere (at one extreme) or a cigar shape (at the other). Ovality is described by a ratio of volume to area:
- O = Ovality
- A = Area
- V = Volume
The ovality of the He atom is 1.0 and that of HC24H (12 triple bonds) is ~1.7.