user1808: 
e4 e5 
d3

At this point, if d3 advances, say at 3. d4 it does not control d4, it is controlled by a sentry (an enemy pawn controlling d4) and is adjacent and behind a same colored pawn at e4. 
Is the d3 pawn backwards? I was told no, because it is supported by c2, but Wikpedia's definition of a backwards pawn doesn't care about a backward's pawn's support, only the support it has moving forward.
Thank you.

user1485: The pawn on d3 is not backwards since (as you say) it is protected by another pawn.
There must be something missing from Wikipedia's definition. Later on the article (http://en.wikipedia.org/wiki/Backward_pawn) contradicts itself.

Also, the opponent can place a piece, usually a knight, on the hole in front of the pawn without any risk of a pawn driving it away.

In your example, if black puts a knight on d4, the pawn move c3will drive it away.

1808: <ol>
<li>e4 e5 </li>
<li>d3</li>
</ol>

<p>At this point, if d3 advances, say at 3. d4 it does not control d4, it is controlled by a sentry (an enemy pawn controlling d4) and is adjacent and behind a same colored pawn at e4. </p>

<p>Is the d3 pawn backwards? I was told no, because it is supported by c2, but Wikpedia's definition of a backwards pawn doesn't care about a backward's pawn's support, only the support it has moving forward.</p>

<p>Thank you.</p>
 1485: <p>The pawn on <code>d3</code> is not backwards since (as you say) it is protected by another pawn.</p>

<p>There must be something missing from Wikipedia's definition. Later on the article (<a href="http://en.wikipedia.org/wiki/Backward_pawn" rel="nofollow">http://en.wikipedia.org/wiki/Backward_pawn</a>) contradicts itself.</p>

<blockquote>
  <p>Also, the opponent can place a piece, usually a knight, on the hole in front of the pawn without any risk of a pawn driving it away.</p>
</blockquote>

<p>In your example, if black puts a knight on <code>d4</code>, the pawn move <code>c3</code>will drive it away.</p>
