The sheep was a very important animal to the ancient Chinese because they were useful for both food, and textles. A healthy sheep could make all the difference for the well-being of a person and their family. Therefore, a large, healthy sheep, was considered both very lucky, and beautiful. "羊大为美 (yáng dà wéi měi) or 羊大即美 (yáng dà jí měi)" translates to "A large sheep is beautiful" is a famous idiom that helps showcase the reason why 羊 Yáng and 大 Dà are combined to form the character for beautiful, 美 Měi.
The Chinese word for the United States of America is "美国 (Měiguó)". 美国 (Měiguó) literally translates to “beautiful country” and is sometimes abbreviated in Chinese simply as "美".