Coriander is the English word, but cilantro is used, especially in the US and in the context of Mexican food.

In Canada it is usually called cilantro, but coriander is also used. No matter what you call it, cilantro/coriander tastes awful! :)

It depends where you are. Because of the popularity of Mexican food in the US, the word 'cilantro' is used in North America. But it wouldn't be understood by speakers of British English - we say 'coriander' in the UK, being more influenced by Asian cuisine.

Es lo mismo.