out-是英语本族语固有的派生词缀，其基本意思就是out。在构词中，out-有两种意思：它能与名词或形容词结合，起修饰作用， 表示 out或outside等意思；它还可以附在动词、名词及某些形容词前面，分别表示more than, to surpass和be more than等意思。注意，在这两种情况下，out-都有可能改变词基单词的词性。

下面先介绍out-用于第一种意思的例子。 

outburst [out- = out 外；burst n. 突发→] n. a burst out 突然爆发 / There comes an outburst of cheers from the audience. 观众突然发出一阵欢呼。

outcry [ out- = out 出;cry n. 哭→]n. a cry out; sudden cry or scream 喊叫；呐喊 / The burglar warned her to make no outcry. 强盗警告她不许叫喊。

outbuilding [ out- = outside 在外；building n. 建筑物→]n. building built outside or near the main building 外层 / Barns are outbuildings on a farm.在农场中谷仓是建在住房外头的。

outdoor [ out- = outside 在外；door n. 门户→]a. outside of houses; in the open air 户外的；露天的 / Outdoor games will make you healthy. 室外活动使人身体健康。

outdoors ad. 在户外；在野外

outgoing [out- = out 出;going a. 进行的→] a. going out; departing 往外去的；出发的 / All the outgoing letters should be examined. 所有发出的信件均要经过检查。

outstanding [ out- = out 出；standing a. 站立的] a. standing out from others; well-known 杰出的，显著的 / He is an outstanding baseball pitcher because of his control.他是个杰出的棒球投球手，因为他控球好。