A code USES symbols to replace words, phrases, or sentences. To read the message of a real code, you must have a code book.

一个密码用符号来代替单词，短语或者句子。想要解读一个真正的密码信息，你必须有一个密码本。

youdao

The dictionary or surface meaning of the words or code used by the sender is not the message.

语言的字典含义或字面含义、说话者运用的规范都不是要表达的讯息。

youdao