The surname Pentecost  usually comes from the Christian (Biblical) date 50 days after the Resurrection of Christ when the church received the gift of the Holy Spirit. The term Pentecost itself is an expression of Biblical Greek, in which "Pentecosti" is translated as "fiftieth day". The Pentecost feast day was widely celebrated all throughout Europe from the middle ages up to modern times and sometimes is referred to as WhitSunday in the UK. The French term is Pentecote. That date (Pentecost) was when the rents were due to the landowner, and crops up a lot when doing online searches--it's easy to get confused when tracing ancestors back to England/Scotland/Wales.Hope this helps some.