Refers to a person's or animal's back. In everyday speech 背中 is often more concrete, but 背 is common in set phrases such as 背を丸める and 背に負う.
I walked hunched over from the cold.
back side; rear side; back of a chair; spine of a book
Used for the back, rear, or spine-like part of certain objects. It is not a general replacement for 裏; common collocations include 椅子の背 and 本の背.
I rested by leaning against the back of the chair.
The title is written on the spine of the book.
Used especially in the pattern 背が高い／低い for a person's height. It refers to stature rather than altitude or the height of an object.
She is the tallest in the class.
mountain ridge
A landform use that treats the ridge or crest of a mountain as its 'back.' 尾根 is the more explicit everyday word for a ridge.
The path continues along the mountain ridge.
He walked with his back hunched against the cold.
He leaned back against the chair and relaxed.
The climbers walked along the ridge toward the summit.
She turned her back angrily.
The title is printed on the spine of the book.
The soldiers walked carrying heavy loads on their backs.
uniform number; shirt number; squad number
spine; backbone; spinal column
stoop; round shoulders; hunched back
standing on tiptoe and stretching; stretching oneself taller · overreaching oneself; trying beyond one's ability; pushing too hard
business suit
stature; height (of a person)
backrest; back of a chair
backstroke
budgerigar; budgie; common pet parakeet
dorsal fin
dashing; gallant; stylish
stature; build; physique
redback spider
my love; my dear; darling · my friend; comrade
round back (book spine)
married couple; husband and wife · brother and sister; siblings
cold mountain wind; cold Pacific wind in Tōhoku summer
signature; print signature
slicing a fish down the back · slit in the back of a garment · split in lumber to prevent cracking
breadth of the back; back width
back door; back entrance
backboard · dorsal plate; tergum
collating mark