A sale is the act of selling a product or service in return for money or other compensation. It is an act of completion of a commercial activity. wikipedia.org

Inbound marketing and its opposite (outbound marketing) have two pairs of meanings depending on the context. wikipedia.org

A sale is the act of selling a product or service in return for money or other compensation. It is an act of completion of a commercial activity. wikipedia.org

Telemarketing (sometimes known as inside sales, or telesales in the UK and Ireland) is a method of direct marketing in which a salesperson solicits prospective customers to buy products or services, either over the phone or through a subsequent face to face or Web conferencing appointment

Lead generation, or lead gen is a marketing tool used, particularly in internet marketing, to generate consumer interest or inquiry into products or services of a business. wikipedia.org

Marketing is the process of communicating the value of a product or service to customers, for the purpose of selling that product or service. wikipedia.org

Email marketing is directly marketing a commercial message to a group of people using electronic mail email. wikipedia.org

A strategy employed by an organization in which a continuous level of engagement is maintained between the organization and its audience. Relationship management can be between a business and its customers (customer relationship management) and between a business and other businesses (business relationship management). wikipedia.org