Cilantro and coriander come from the same plant, so the difference is really about naming and parts: American English uses cilantro for the fresh leaves and coriander mainly for the dried seeds, while British English calls both the fresh leaves and the seeds coriander. A useful hook: in the US, leaves are cilantro, seeds are coriander; in the UK, both are coriander.
The core difference
Cilantro and coriander name the same plant, but American usage splits the word by plant part while British usage does not.
- cilantro — the fresh leaves and stems of the coriander plant, used as a herb (mainly American usage): Top the tacos with fresh cilantro and lime.
- coriander — the herb's fresh leaves in British usage, or the dried round seeds used as a spice in both varieties of English: The recipe calls for a teaspoon of ground coriander.
How to tell them apart
The plant is a single one, so the trick is remembering which English splits the name and which does not. American English keeps cilantro for the leafy herb and saves coriander for the dried seeds sold as a spice. British English does not make that split: it calls the fresh leaves coriander as well, alongside coriander seeds.
The mix-up shows up most often in recipes that travel across the Atlantic: a US recipe telling you to garnish with cilantro means the same leaves a UK recipe would tell you to garnish with coriander, but a jar labelled coriander in a British kitchen could be either the leaf or the seed depending on context.
