<p>According to Donald Knuth, it's the same.
Here is the link on his paper about Dancing Links algorithm, which is used to solve such "non-tree" problems as N-queens and Sudoku solver.</p>

<blockquote>
  <p><a href="https://arxiv.org/pdf/cs/0011047.pdf" rel="noreferrer">Backtracking, also called depth-first search</a></p>
</blockquote>
What's the difference between backtracking and depth first search?
<p>What's the difference between backtracking and depth first search?</p>