noun
Tabanus trigonus (a species of horsefly)
A specific species of horsefly found in Japan; the name is usually written in katakana as ウシアブ.
ウシアブは牛や馬の血を吸う大型のアブです。
The ushiabu is a large horsefly that sucks the blood of cattle and horses.
アブ is the general term for horseflies, while ウシアブ refers specifically to the species Tabanus trigonus.
Compound of 牛 (ushi, 'cattle') and 虻 (abu, 'horsefly'), referring to its habit of biting cattle.