This phenomenon is mostly popular amongst teenagers, but there's no doubt whatsoever that older OR younger people than teenagers can "fika". And there is nothing that hinders you from "fikaing" at home, with your home-made cookies or coffee! It's just that it's more common that younger people use the word "Fika", when they practice this in local coffee-shops and such. It's a way of getting together with friends, workmates, a date, etc, chatting in a relaxed kind of way
Another definition is simply just having coffee or tea, but this does not complete the picture of what "fika" can be.
The word is, as you may have figured out, a noun and adjective at the same time. Let me just show you how we use the word in the swedish language (but i use the english words to show what context it is in).
The following are the Swedish inflections partially integrated with english grammar, which I advice english speaking people to use in the English language!
Inflections entirely used with english grammar only distorts the word, and what actually sounds like.
It is not hard to learn these inflections, even if they are indifferent to real english grammar. Just fika regularly, you will learn pretty fast!
I "fikade" last friday! f i* k a* d e*
Have you ever "Fikat"? f i* k a* t
I am "fikaing"! f i* k a* i* n g
i* - (sp>ee<d)
a* - (>a<nother)
e* - (h>e<nce)
Hey guys, do you want to meet up and fika?