Teeth \Teeth\, v. i. [imp. & p. p. Teethed; p. pr. & vb. n. Teething.] To breed, or grow, teeth.
Source: Webster's Revised Unabridged Dictionary (1913)
Teething \Teeth"ing\, n. The process of the first growth of teeth, or the phenomena attending their issue through the gums; dentition.