Why trie is also called "prefix tree"? - data-structures

Question

I was reading this article on Wikipedia and stumbled on the line which says "trie is also called prefix tree".
I know the usage of trie but why is it called "prefix tree"?

Answer 1

As they can be searched by prefixes. You can also reverse the trie and find wildcards: http://phpir.com/tries-and-wildcards.
For example the term academic would be c-i-m-e-d-a-c-a. Using the same
technique as before we can now search for all words that end with a
certain phrase, allowing us to handle wildcards at the beginning of
query terms, e.g. *cademically.
<?php
function buildTries($words) {
$trie = new Trie();
$rtrie = new Trie();
foreach($words as $word) {
$trie->add($word);
$rtrie->add(strrev($word));
}
return array('trie' => $trie, 'rtrie' => $rtrie);
}
function searchTries($search, $tries) {
$terms = explode('*', $search);
if(count($terms) > 2) {
return false;
}
if(strlen($terms[0]) && strlen($terms[0])) {
// middle wildcard
$straight = $tries['trie']->prefixSearch($terms[0]);
$rev = $tries['rtrie']->prefixSearch(strrev($terms[1]));
return array_intersect($straight, reverseArray($rev));
} else if(strlen($terms[1]) ) {
// leading wildcard
return reverseArray($tries['rtrie']->prefixSearch(strrev($terms[1])));
} else {
// trailing wildcard
return $tries['trie']->prefixSearch($terms[0]);
}
}
function reverseArray($keys) {
$return = array();
foreach($keys as $key => $value) {
$return[strrev($key)] = $value;
}
return $return;
}
/* Do some searches */
$words = array(
'adder',
'addled',
'abject',
'agreement',
'astronaut',
'handily',
'happily',
'helpfully'
);
$tries = buildTries($words);
$return = searchTries('h*ly', $tries);
var_dump($return);
$return = searchTries('ha*ly', $tries);
var_dump($return);
?>
The results from the two var dumps look like this:
array(3) {
["handily"]=>
NULL
["happily"]=>
NULL
["helpfully"]=>
NULL
}
array(2) {
["handily"]=>
NULL
["happily"]=>
NULL
}