GCSE vs IGCSE

Hi, so I have heard people use the phrase gcse and igcse... are they the same thing? Whats the difference?

GCSE is the standard school qualification designed to be taken at the end of year 11 in the UK education system (except scotland) the content of the specfications, quality standards and the implementation of exams is under the ultimate control of govenment agencies.
International GCSE (IGCSE) are designed to be of a similar standard but for use in schools outside of the UK. Their content is not controlled by UK government agencies but by the examiners that create them. They can't be used in UK state schools that are government funded but can optionally be used in independent schools and by independent learners.
They are favoured by independent learners because the assessment in usually examination based, they don't generally have coursework or practical tests.