There are several ways to name a (.) punctuation mark. I can't understand if they anyhow differ?
- Full stop (also Fullstop)
- Full point
I only use the word "period".
When used to mark the end of a sentence or an abbrevation, period is the common term in the US and Canada. The rest of the English-speaking world (UK, Australia, New Zealand, South Africa, etc.) prefers full stop. Full point is an archaic synonym of these, but no longer used anywhere.
When it is used with numbers, point is used, e.g. 3.6 is pronounced "three point six". Dot tends to be used when giving the name of a website, e.g. "amazon dot com".