lexicon-a list of words on a particular subject or in a language in alphabeical order
按照某一特定主题而列出的词汇（分类词典）
dictionary-a book that gives a list of the words of a language in alphabetical order and explians what they mean or gives a word for them in a foreign language
可以理解为词典的统称,按照字母顺序排列,