5. (Nat. Hist.) An angular or prominence on any edge; as, a tooth on the scale of a fish, or on a leaf of a plant; specifically (Bot.), one of the appendages at the mouth of the capsule of a moss. See Peristome.

6. (Zo["o]l.) Any hard calcareous or chitinous organ found in the mouth of various invertebrates and used in feeding or procuring food; as, the teeth of a mollusk or a starfish.

In spite of the teeth, in defiance of opposition; in opposition to every effort.

In the teeth, directly; in direct opposition; in front. ``Nor strive with all the tempest in my teeth.'' --Pope.

To cast in the teeth, to report reproachfully; to taunt or insult one with.

Tooth and nail, as if by biting and scratching; with one's utmost power; by all possible means. --L'Estrange. ``I shall fight tooth and nail for international copyright.'' --Charles Reade.

Tooth coralline (Zo["o]l.), any sertularian hydroid.

Tooth edge, the sensation excited in the teeth by grating sounds, and by the touch of certain substances, as keen acids.

Tooth key, an instrument used to extract teeth by a motion resembling that of turning a key.

Tooth net, a large fishing net anchored. [Scot.]

--Jamieson.

Tooth ornament. (Arch.) Same as Dogtooth, n., 2.

Source: Webster's Revised Unabridged Dictionary (1913)