Use of name attribute

HTML-CSS
1

**i got the program but i’m not understanding the use of name attribute


<h2>CatPhotoApp</h2>
<main>
  <p>Click here to view more <a href="#">cat photos</a>.</p>
  
  <a href="#"><img src="https://bit.ly/fcc-relaxing-cat" alt="A cute orange cat lying on its back."></a>
  
  <p>Things cats love:</p>
  <ul>
    <li>cat nip</li>
    <li>laser pointers</li>
    <li>lasagna</li>
  </ul>
  <p>Top 3 things cats hate:</p>
  <ol>
    <li>flea treatment</li>
    <li>thunder</li>
    <li>other cats</li>
  </ol>
  <form action="/submit-cat-photo">
    <input type="text" placeholder="cat photo URL" required>
   <label for="indoor">
      <input id="radio" type="radio" >indoor
   </label>
    <button type="submit">Submit</button>
    <label>
      <input type="radio" >outdoor
   </label>
  </form>
</main>

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.84 Safari/537.36.

Link to the challenge:
https://learn.freecodecamp.org/responsive-web-design/basic-html-and-html5/create-a-set-of-radio-buttons

2

When you read the lesson provided with the challenge , you can see

<label> 
  <input type="radio" name="indoor-outdoor">Indoor 
</label>

this input element has a name attribute set to indoor-outdoor