
GIF (Graphics Interchange Format). One of the two most common graphics formats on the Web. (JPEG is the other.) GIF images are used mostly for line art, logos and similar types of graphics.
Giveaway. A gift given to potential customers at trade shows and other marketing events to remind them of a product or service. Also known as a "freebie" or a "gimme."
Guarantee. A promise to step in and perform another´s obligation if that person should fail or default.
Guarantor. A person who makes a legally binding promise either to pay another person´s obligation or to perform another person´s duty if that person defaults or fails to perform.

Hard Sell. Aggressive, high-pressure sales techniques.
Health Maintenance Organization (HMO). A system of managed health care in which patients must see approved health care providers. HMOs typically offer coverage with no deductibles and low per-visit fees.
HTML (Hypertext Markup Language). One of the foundations of the Web, HTML is a text-based language used to describe the structure and layout of a document — headlines, paragraphs, table elements and so on.
HTTP (Hypertext Transfer Protocol). The set of standards that lets Web servers and browsers communicate with each other.
HVAC. Acronym that stands for heating, ventilation and air conditioning.
Hyperlink (link). Web developers use HTML to create hyperlinks that a user clicks on to be transported to another Web page. Hyperlinks can appear as graphics or as areas of differently colored or underlined text.