A board foot is one foot long, one foot wide and one inch in thickness. Checking the Waste Mary Huston Gregory This is usually expressed in pounds per thousand board feet, a board foot being considered as one-twelfth of a cubic foot.
Sibilance is a manner of articulation of fricative and affricate consonants, made by directing a stream of air with the tongue towards the sharp edge of the teeth, which are held close together; a consonant that uses sibilance may be called a sibilant, or a strident.
Absorbance is a measure of the amount of light with a specified wavelength that a given material prevents from passing through it. Absorbance does not necessarily measure the amount of light that the material absorbs. For example, absorbance would also include light that is dispersed by the sample material.