Thanks for everybody's replies.
I had wondered about 'organist' - I thought 'organiser' from Google a little unlikely!
But I wondered of they had organs and organists in 1618.
Wikipeadia tells me that organs have been around a long, long time, and it looks quite feasible that there were organs in churches, at this time.
That looks like an informative site jaygee, and also the 1702 Dictionary hanes teulu.
Thanks for those.
Interesting where this genealogy stuff takes you!