llano (n.)youdaoicibaDictYouDict[llano 词源字典]
1610s, American Spanish, "prairie," from Spanish llano "plain, even, level, smooth," ultimately from Latin planum "plain," from planus "smooth" (see plane (n.1)). Hence, llanero "a Latin-American cowboy" (1819), literally "plainsman."[llano etymology, llano origin, 英语词源]