Plural of smoothness when referring to countable objects

Question

Hello,I am a mathematician and in my research area we often discuss about the smoothness of certain objects.I was wondering if it is correct to use the plural form "smoothnesses" when referring to the smoothness of countable (say 3) objects. I would be grateful if anyone has a reference from a good source.Thanks in advance for the help,Sergios

AlpheccaStars · Accepted Answer

Smoothness is normally uncountable. It is the characteristic of an object.

For example:

The smoothness of a golf ball is much less than that of a bowling ball.
A bowling ball, a ping pong ball and a billiard ball are comparable in smoothness.

It seems quite awkward to use the plural form... so I would avoid sentences of following type, and use the one above instead.

(Ugh!) The smoothnesses of a bowling ball, a ping pong ball and a billiard ball are comparable.

For mathematics, use something like "the measure / degree of smoothness" if you are comparing the extent of roughness or smoothness of a physical object which can be measured or otherwise determined.

e.g.

The smoothness measures (average deviation from the ideal sphere as a percent of radius) of a bowling ball, a ping pong ball and a billiard ball are 0.1%, 0.001% and 0.02%, respectively.

Plural of smoothness when referring to countable objects

Top answer

Get the Weekly English Kit 📬

Related Questions