What is "adric"

Adric is a fictional character played by Matthew Waterhouse in the long-running British science fiction television series Doctor Who. He was a young native of the planet Alzarius, which exists in the parallel universe of E-Space. A companion of the Fourth and Fifth Doctors, he was a regular in the programme from 1980 to 1982 and appeared in 11 stories (40 episodes). The name Adric is an anagram derived from Nobel Prize-winning physicist Paul Dirac. Waterhouse is the youngest male actor to play a companion so far in the series.