明喻（simile）表示“……像……”，表示两者之间的相似性，所以使用like或as的短语；而暗喻或隐喻（metaphor）表示“……是……”，即把“像”的意思隐含起来，故不连用as, like短语。如：

“She’s as fierce as a tiger” is a simile, but “She's a tiger when she's angry” is a metaphor. “她像老虎一样凶”是明喻，而“她生气时就是只老虎”是隐喻。

隐喻不连用as, like短语，即把本来是比喻的东西当作事实来写，所以不可能有固定的句型，又如：

“The mind is an ocean” and “the city is a jungle” are both metaphors. “思维是海洋”和“城市是丛林”都是隐喻。

“Her words were a knife in his heart” is a metaphor. “她的话是插在他心头的一把刀”是隐喻。

“He is a pig” is a metaphor, and “he behaves like a pig” is a simile. “他是一头猪”是明喻，“他的举止就像一头猪”是隐喻。

“He was drowning in paperwork” is a metaphor in which having to deal with a lot of paperwork is being compared to drowning in an ocean of water. “他被淹没在文书工作中”是一种隐喻，把不得不处理大量的文书工作比喻为淹没在海洋里。

隐喻或暗喻不一定是句子，有时也可能是一个短语。如：

“A river of tears” is a metaphor. “泪河”是个暗喻。

“A heart of stone” is a metaphor. “铁石心肠”是个隐喻。