[Rails] Rails tutorial; CRD working, U failing

Using http://guides.rubyonrails.org/getting_started.html as a guide.
  Create, Read, Delete all work. Update fails:

NoMethodError in WordsController#update

private method `update' called for #<Word:0xae98360>

(I chose to make a list of words rather than of posts.)


The Request parameters:

{"utf8"=>"✓",
  "_method"=>"put",
  "authenticity_token"=>"HizJaASbs53QXfgRZk8SbZ+6OcDigR7LtDtpEGHXwMY=",
  "word"=>{"word"=>"feline",
  "definition"=>"Like a cat; stealthy"},
  "commit"=>"Update Word",
  "id"=>"3"}

The "update" method from the controller:

class WordsController < ApplicationController
...
   def update
     @word = Word.find(params[:id])

     if @word.update(params[:definition])
       redirect_to @word
     else
       render 'edit'
     end
   end


rake routes:
...
       PUT /words/:id(.:format) words#update
...

Context information:
rails -v
Rails 3.2.2

ruby -v
ruby 1.9.3p125 (2012-02-16 revision 34643) [i686-linux]

In case relevant: CentOS release 5.5 (Final)


I'm sure this is a simple thing and may have to do with a different version
of Rails. However, I've not had success pursuing that line.

Does anyone have a good idea why I'd be getting the error on the update
method?

Thanks!