sierra
/sɪˈeərə/noun
1
- (especially in Spanish-speaking countries or the western US) a long jagged mountain chain（尤指西班牙语国家或美国西部的）锯齿山脊。
2
- a code word representing the letter S, used in radio communication（无线电通讯用的）字母S的代称。
词源
mid 16th cent.: Spanish， from Latin serra 'saw'.