Boston Fern The most common indoor fern, Boston ferns are long-lived plants that can reach more than 5 feet tall and wide at maturity (though indoors they rarely reach that size). Fern breeders have released a large number of varieties -- from selections with golden fronds to fantastically frilled fronds.
Wiktionary(0.00 / 0 votes)Rate this definition: 1  green room(Noun) (entertainment) In a television studio, theatre or concert hall, the room where performers await their entrance. 2  green room(Noun) The inside of a tube (ie. of a wave making a tube).
The concept behind a cleanroom is to push air into the room from the top (green. arrows), down into the room, and then out vents at the floor level (blue arrows), carrying wth it any contaminants from the manufacturing process. ISO Class 4 = Federal standard Class 10.