Legio II Brittannica: one of the legions of the later Roman empire. Its name means, as one may have already guessed, "second British legion".
The only source for the name of this legion is the text known as Notitia Dignitatum, which is a catalogue of Roman magistracies and military units in the last decade of the fourth century. Other sources have other names (e.g. Secundani Brittones).
It has been assumed that II Brittannica originated as a mobile unit of II Augusta, which later became an independent legion, used in the coastal defense against the Saxons. It is not known when this happened, but perhaps the proud name of the legion (cf. the more modest names "First legion of the Noricans") suggests that it was created in the years 286-297, when Britain was briefly independent under the usurpers Carausius and Allectus.