- a box or tray, as on an office worker's desk, into which new memos, mail, etc. are placedalso written in box
- a folder, as in e-mail software, in which received or unread messages are automatically storedalso written inbox
in-box

MLA Style
"in-box." YourDictionary, n.d. Web. 14 January 2019. <https://www.yourdictionary.com/in-box>.
APA Style
in-box. (n.d.). Retrieved January 14th, 2019, from https://www.yourdictionary.com/in-box
(plural in-boxes)
- A container in which all the papers to be dealt with are put.
- (computing) an electronic folder serving the same purpose.
- (figuratively) The aggregate of items that demand one's attention or effort.
- The kids, my ex, my parents, the job, bills — my in-box is full.
(third-person singular simple present in-boxes, present participle in-boxing, simple past and past participle in-boxed)
- To put in (someone's) in-box.
- I just in-boxed you the presentation.
in + box
MLA Style
"in-box." YourDictionary, n.d. Web. 14 January 2019. <https://www.yourdictionary.com/in-box>.
APA Style
in-box. (n.d.). Retrieved January 14th, 2019, from https://www.yourdictionary.com/in-box