The Collaborative International Dictionary
Interdental
Interdental \In`ter*den"tal\, a.
Situated between teeth; as, an interdental space, the space between two teeth in a gear wheel.
(Phon.) Formed between the upper and lower teeth; as, interdental consonants.
Wiktionary
interdental
a. 1 Pertaining to the space between the teeth. 2 (context phonetics English) Pronounced with the tongue between the top and bottom teeth. n. (context phonetics English) A speech sound pronounced with the tongue between the top and bottom teeth.