剑桥词典a dot followed by three letters , such as .doc or .jpg, that forms the end of the name of a computer document （計算機）文件擴展名（． 後跟三個字母，如 ．doc 或 .jpg，形成的計算機文件擴展名） Be sure to type in the document name and file extension before you click "save ". 在點“保存”前要輸入文件名和擴展名。 返回 file extension