SOAP - Simple Object Access Protocol

SOAP in short -

Web services are used to handle interoperability problem and have given a way to exchange the data in different platforms.

It uses Simple Object Access Protocol (SOAP) to transport data over networks. XML is widely used for structuring, coding data and decoding data.

SOAP is XML based protocol, format-for-sending-messages and used over HTTP.

For more brief, please refer below link-

http://searchsoa.techtarget.com/definition/SOAP