[ 'ekstrә ]
pref. 在...之外, 超出, 越出
[医] 外, 在外, 额外
A Latin preposition, denoting beyond, outside of; -- often
used in composition as a prefix signifying outside of, beyond, besides,
or in addition to what is denoted by the word to which it is prefixed.
英汉双解字典由 ECDICT 提供