Is the word period same as fullstop?

Yes, "period" is the same as "full stop" in the context of punctuation. They both refer to the punctuation mark (.) used to end a sentence.

However, "period" can also refer to other things, like a menstrual period, a specific time span, or a geological period. So, while it's safe to assume someone means punctuation when they say "period," it's always a good idea to consider the context.