Cotton
noun
Cotton that comes off a tree is still cotton!
もめん
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own as long as you watch out for 木. It drops the く from もく making this reading just もめん.
木綿のハンカチをプレゼントしてもらいました。
I got this cotton handkerchief as a present.