Theognostus the Grammarian

Theognostus the Grammarian (Greek: Θεόγνωστος ὁ Γραμματικός; Latin: Theognostus Grammaticus) was a 9th-century writer, known for his book Canons (Canones in Latin and most citations). This work is one of the source texts for A Greek-English Lexicon, a standard work on the Ancient Greek language. He also wrote a lost historical work.