Not ponderable; without sensible or appreciable weight; incapable of being weighed.
Difficult or impossible to comprehend or evaluate.
An imponderable question.
A factor that cannot be anticipated.
An imponderable substance or body; specifically, in the plural, a name formerly applied to heat, light, electricity, and magnetism.
Being, or having the salient properties of, a monotone function.
Having a single unvaried pitch.
A piece of writing in one strain throughout.
A single unvaried tone of speech or a sound.
To speak in a monotone.