setting the right views argument type
It all depends on what that word is.  For example, if 'practice' is a taxonomy term name, you would choose that and Views would filter on nodes tagged with taxonomy term 'practice.'  If, however, the word was the title of a node, you would filter on node title and Views would filter on node titles equal to 'practice.'

ADDITION:

If you want to ignore the word when it comes to filtering, just use the Global Null field and it will be ignored by any queries, but will still be available as arg(#) in any script called.

ADDITION 2:

Let's say you are looking at a Views Page Display, with a path something like:

www.user1015214.com/all/the/best


that returns pictures of all the best stuff a website has to offer.  Views would have that with a path of all/the/best.  Now, let's say we wanted filter this by something, we'd change that path to all/the/best/% and then enter an argument (D6) or contextual filter (D7).  Let's say it's a taxonomy term for this example.  So now we could have something like this:

www.user1015214.com/all/the/best/views


and it would return all the best stuff the website has to offer that is tagged with the term views.  Now, let's say you want to have an easter egg feature, where if you have polite users, they get something special, so in Views, you can add another argument to the path, eg, all/the/best/%/% and in this second argument you give tell Views it is a Global Null Value.  Now, what this does is let Views know to look for an argument there, but not to use it in any of the sql it builds.  Like a placeholder.  So, now you could do something like:

www.user1015214.com/all/the/best/views/please


And Views would create the same sql statements as before, returning all the best views, but you could then access that additional argument for any custom purpose you wanted anywhere within the drupal system.  The easiest is to use the system arg(#) function:

$foo=arg(0); // all
$bar=arg(2); // best
$baz=arg(4); // please


and in your example, within the your node template file, you could do something like:

$baz=arg(4);
if ($baz=='please') {
   print '&lt;div class="polite"&gt;Thank\'s for being polite! Here\'s a link to something special: ';
   print l('Pee Wee\'s Playhouse', 'http://www.peeweesplayhouse.com') . '&lt;/div&gt;';
}


and then whenever someone asked nicely that additional  would be displayed along with your node.  Pretty nonsensical I realize, but I hope it explains arg()s :)