What is the difference between 背 and 裏 for the backside of objects?


I know that 背 can also mean height, and also refers to the spine of the book
when used with books. I also know that 椅子の裏 refers to the bottom of the chair
while 椅子の背 refers to the back of the chair. But beyond that, if I am to use
them with normal objects, what is the difference? For example, is there a
difference between 窓の裏 and 窓の背 or 扇風機の裏 and 扇風機の背?




I was browsing
[BCCWJ](https://bonten.ninjal.ac.jp/bccwj/string_search?commit=%E6%A4%9C%E7%B4%A2&string_search%5Bgenres%5D=PN_core%2CPN%2CPM_core%2CPM%2CPB_core%2CPB%2CLB_core%2CLB%2COW%2COB%2COC_core%2COC%2COY_core%2COY%2COL%2COM%2COP%2COT%2COV&string_search%5Bwords%5D=%E3%81%AE%E8%83%8C%E3%81%AB&string_search%5Byears%5D=1971%2C1972%2C1973%2C1974%2C1975%2C1976%2C1977%2C1978%2C1979%2C1980%2C1981%2C1982%2C1983%2C1984%2C1985%2C1986%2C1987%2C1988%2C1989%2C1990%2C1991%2C1992%2C1993%2C1994%2C1995%2C1996%2C1997%2C1998%2C1999%2C2000%2C2001%2C2002%2C2003%2C2004%2C2005%2C2006%2C2007%2C2008&utf8=%E2%9C%93)
with the keyword='の背に'. 背 in the meaning of the question is used for 椅子, ソファ,
フォーク. As you mention in the question, it can be used for books as well.
Practically these are pretty much all for which 背 in that sense can be used.
(Cf. As regards with books, it is one of [many
jargons](https://www.library.pref.osaka.jp/site/osaka/book-parts.html).)

I cannot come up with other objects for which the usage extends naturally.

I guess 窓 is too symmetrical to call one side 背. Using 背面 may be possible, but
usually 内/外側 will be used.

As for 扇風機, the part connecting the fan part and the bottom part won't be
called 背. 首 is possibly a term to call it although I never really thought
about where exactly 扇風機の首 refers. The related expression commonly used is 首振り
which means the head of 扇風機 swinging.




I was browsing
[BCCWJ](https://bonten.ninjal.ac.jp/bccwj/string_search?commit=%E6%A4%9C%E7%B4%A2&string_search%5Bgenres%5D=PN_core%2CPN%2CPM_core%2CPM%2CPB_core%2CPB%2CLB_core%2CLB%2COW%2COB%2COC_core%2COC%2COY_core%2COY%2COL%2COM%2COP%2COT%2COV&string_search%5Bwords%5D=%E3%81%AE%E8%83%8C%E3%81%AB&string_search%5Byears%5D=1971%2C1972%2C1973%2C1974%2C1975%2C1976%2C1977%2C1978%2C1979%2C1980%2C1981%2C1982%2C1983%2C1984%2C1985%2C1986%2C1987%2C1988%2C1989%2C1990%2C1991%2C1992%2C1993%2C1994%2C1995%2C1996%2C1997%2C1998%2C1999%2C2000%2C2001%2C2002%2C2003%2C2004%2C2005%2C2006%2C2007%2C2008&utf8=%E2%9C%93)
with the keyword='の背に'. 背 in the meaning of the question is used for 椅子, ソファ,
フォーク. As you mention in the question, it can be used for books as well.
Practically these are pretty much all for which 背 in that sense can be used.
(Cf. As regards with books, it is one of [many
jargons](https://www.library.pref.osaka.jp/site/osaka/book-parts.html).)

I cannot come up with other objects for which the usage extends naturally.

I guess 窓 is too symmetrical to call one side 背. Using 背面 may be possible, but
usually 内/外側 will be used.

As for 扇風機, the part connecting the fan part and the bottom part won't be
called 背. 首 is possibly a term to call it although I never really thought
about where exactly 扇風機の首 refers. The related expression commonly used is 首振り
which means the head of 扇風機 swinging.

