Yes, fern is a Scrabble word!
...and is worth 7 points in Scrabble, and 8 points in Words with Friends
fern
Noun
1. Any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by spores
What Scrabble words can I make with the letters in fern?
3 Letter Words
2 Letter Words