Communication is about passing messages between people or organisations. Messages between a sender and receiver take place using a medium such as email or phone.
One-way communication is when the receiver cannot respond to a message. Two-way communication is when the receiver can respond to a message. This allows confirmation the message has been both received and understood.
Types of communication
There are a number of technical terms you need to learn:
internal communications happen within the business
external communications take place between the business and outside individuals or organisations
vertical communications are messages sent between staff belonging to different levels of the organisation hierarchy
horizontal communications are messages sent between staff on the same level of the organisation hierarchy
formal communications are official messages sent by an organisation, eg a company memo, fax or report
informal communications are unofficial messages not formally approved by the business, eg everyday conversation or gossip between staff
a channel of communication is the path taken by a message