Can SMTP be used to receive email?

The Simple Mail Transfer Protocol (SMTP) is used for sending and receiving e-mail between e-mail clients and servers. When an SMTP server receives an e-mail from a mail client, the SMTP server will then check the MX records for the domain in the e-mail address in order to exchange the mail with the remote SMTP server.

Is SMTP incoming or outgoing?

SMTP (“Simple Mail Transfer Protocol”) is used for sending and delivering from a client to a server via port 25: it's the outgoing server. On the contrary, POP (“Post Office Protocol”) allows the user to pick up the message and download it into his own inbox: it's the incoming server.