triliteral
1 of 2adjective
tri·lit·er·al (ˌ)trī-ˈli-t(ə-)rəl 
: consisting of three letters and especially of three consonants
triliteral roots in Semitic languages
triliteralism
(ˌ)trī-ˈli-t(ə-)rə-ˌli-zəm
noun triliteral
2 of 2noun
: a root or word that is triliteral
Word History
Etymology
Adjective
tri- + Latin littera letter
First Known Use
Adjective
1751, in the meaning defined above
Noun
circa 1828, in the meaning defined above