What tags are used to define the terms and their definitions in a definition list?

The <dl> tag is used to define a definition list in HTML. Each term and its definition are defined using the <dt> and <dd> tags, respectively. The <dt> tag is used to define the term (the word being defined) and the <dd> tag is used to define its definition. Here's an example:

<dl>
  <dt>HTML</dt>
  <dd>HyperText Markup Language - a markup language used to create web pages.</dd>
  
  <dt>CSS</dt>
  <dd>Cascading Style Sheets - a style sheet language used for describing the presentation of a document written in HTML.</dd>
  
  <dt>JavaScript</dt>
  <dd>A high-level, interpreted programming language used to create interactive websites and web applications.</dd>
</dl>

In this example, "HTML", "CSS", and "JavaScript" are the terms being defined and their respective definitions are defined using the <dd> tag.