coriander is the seeds. cilantro is the leaves and stem. I don’t like coriander either.
It’s both.
Coriander seems to have been cultivated in Greece since at least the second millennium BC. One of the Linear B tablets recovered from Pylos refers to the species as being cultivated for the manufacture of perfumes; it apparently was used in two forms: as a spice for its seeds and as a herb for the flavour of its leave