Merriam-Webster
http://www.m-w.com/
以define为例（下面是查询结果）：
define
One entry found for define.
Main Entry: de·fine
Pronunciation: di-'fIn
Function: verb
Inflected Form(s): de·fined; de·fin·ing
Etymology: Middle English, from Latin definire, from de- + finire to limit, end, from finis boundary, end
transitive verb
1 a : to determine or identify the essential qualities or meaning of b : to discover and set forth the meaning of (as a word) c : to create on a computer
2 a : to fix or mark the limits of : DEMARCATE b : to make distinct, clear, or detailed especially in outline
