Duo is rather mean! No mention of the word 'dot'in the hints. And its a new word!
Period as meaning a point is quite specifically American English.
What word is used in England?
In British English they call it full-stop :D
I have never heard period used to mean full stop outside the USA.
Period meaning 'full stop' was used in the UK when I was at school way back in the sixties and seventies but is less common now.
What are the contexts in which you can use this word?
I put in point, wouldn't except?