Is
From Simon Online
Is grece per dipthongum est ovis que et provaton dicitur.
Translation:
The Greek word Is, written with a diphthong, means in Latin ovis {"sheep"}, and another Greek name for the animal is provaton.
Commentary:
Simon refers to Greek οἶς /oîs/, "sheep", pointing out its archaic spelling with a diphthong in contrast to the late Greek non-diphthongal pronunciation /is/; and he mentions the synonym πρόβατον /próbaton/, which originally referred to cattle but was later used almost exclusively for sheep. Again Simon's spelling reflects the late Greek pronunciation /provaton/.