線上字典 On-line Dictionary

1. Merriam-Webster - http://www.m-w.com/

2. Cambridge - http://dictionary.cambridge.org/

3. Oxford - http://www.oup.com/elt/catalogue/teachersites/oald7/?cc=tw

4. Wikipedia -https://zh.wikipedia.org/wiki/Wikipedia:%E9%A6%96%E9%A1%B5

5. Your Dictionary - http://www.yourdictionary.com/index.shtml