書箱 is read as しょそう (shosou) and means bookcase.
しょそう
shosou
しょかんばこ
electronic mailbox
ししょばこ
post office box
とうしょばこ
suggestion box
ゆうびんししょばこ
ししょばこばんごう
Post Office box address
はこがき
autograph or note of authentication written on a box containing an art work
しょき
clerk
しょるい
document
かきとり
transcription (of spoken material)
かきとめ
registered mail
かきなおす
to write out
かきとめる
to write down