A quadriliteral is a consonantal root containing a sequence of four consonants (instead of three consonants, as is more often the case). A quadriliteral form is a word derived from such a four-consonant root. For example, the abstract quadriliteral root t-r-g-m / t-r-j-m gives rise to the verb forms "tirgem" in Hebrew, "tarjama" in Arabic, ተረጐመ "täräggwämä" in Amharic, all meaning "he translated". In some cases, a quadriliteral root is actually a reduplication of a two-consonant sequence. So in Hebrew "digdeg" means "he tickled", and in Arabic "zilzāl" means "earthquake".