Vocabulary : Fluctuability to Fluency

Fluctuability : The capacity or ability to fluctuate.
Fluctuant : Moving like a wave; wavering ;; showing undulation or fluctuation; as, a fluctuant tumor. ;; Floating on the waves.
Fluctuate : To move as a wave; to roll hither and thither; to wave; to float backward and forward, as on waves; as, a fluctuating field of air. ;; To move now in one direction and now in another; to be wavering or unsteady; to be irresolute or undetermined; to vacillate. ;; To cause to move as a wave; to put in motion.
Fluctuated : of Fluctuate
Fluctuating : of Fluctuate

Fluctuation : A motion like that of waves; a moving in this and that direction; as, the fluctuations of the sea. ;; A wavering; unsteadiness; as, fluctuations of opinion; fluctuations of prices. ;; The motion or undulation of a fluid collected in a natural or artifical cavity, which is felt when it is subjected to pressure or percussion.
Flue : An inclosed passage way for establishing and directing a current of air, gases, etc.; an air passage ;; A compartment or division of a chimney for conveying flame and smoke to the outer air. ;; A passage way for conducting a current of fresh, foul, or heated air from one place to another. ;; A pipe or passage for conveying flame and hot gases through surrounding water in a boiler; -- distinguished from a tube which holds water and is surrounded by fire. Small flues are called fire tubes or simply tubes. ;; Light down, such as rises from cotton, fur, etc.; very fine lint or hair. ;; In an organ flue pipe, the opening between the lower lip and the languet.
Flue pipe : A pipe, esp. an organ pipe, whose tone is produced by the impinging of a current of air upon an edge, or lip, causing a wave motion in the air within; a mouth pipe; -- distinguished from reed pipe. Flue pipes are either open or closed (stopped at the distant end). The flute and flageolet are open pipes; a bottle acts as a closed pipe when one blows across the neck. The organ has both open and closed flue pipes, those of metal being usually round in section, and those of wood triangular or square.
Fluence : Fluency.
Fluency : The quality of being fluent; smoothness; readiness of utterance; volubility.