"Subconcave" is a word in ENGLISH

Three cowboys of the world are sitting around camp talking about how tough they were and the tales kept getting bigger and bigger. The cowboy from Australia says, "I wrestled a 200 pound crocodile and may it cry like a baby." The Cowboy from Brazil shakes his head and says, "I killed a 400 pound steer with my bare hands." The Cowboy from Texas just smiled and kept stirring the campfire with his leg.