背嚢 is read as はいのう (hainou) and means knapsack.
はいのう
hainou
せおう
to carry on one's back
せたけ
stature
しょいなげ
seoi nage (judo)
せなか
back (of the body)
はいけい
backing
せびろ
business suit
せい
height
せぼね
spine
せのび
standing on tiptoe and stretching one's back to make oneself taller
はいご
back
はいにん
breach of trust
せすじ
seam down the back (of clothing)