title: Confused about R terminology: Attributes, parameters, and arguments
body: <p>Once and for all I want to get the R terminology right. However, none of the books I was reading was of big help, and it seems to me the authors choose the names sometimes arbitrarily. So, my question is when exactly are the names "attribute", "parameter", and "argument" used?</p>
  
  <p>From what I read and understood so far, a parameter is what a function can take as input. For example if I have a function that calculates the sum of two values, <code>sum(value1, value2)</code>, 'value1' and 'value2' are the function's parameters.</p>
  
  <p>If we are calling a function, we call the values passed to the function arguments. For the sum-function example, "23" and "48" would be the function arguments for:</p>
  
  <pre><code>sum(23,48).
  </code></pre>
  
  <p>So basically we call it parameter when we define a function, and we call it argument when we call the function (so the arguments are passed to the function's parameters)</p>
  
  <p>But what about "attributes"? From what I understand, attributes are the equivalent of parameters in methods (and methods are functions of a class object)?</p>
  
  <p>For example, if I would have something like:</p>
  
  <pre><code>heatmap(myData, Colv=NA, Rowv=NA)
  </code></pre>
  
  <p>... , would 'myData' be an argument or attribute? And what about <code>Colv=NA</code> and <code>Rowv=NA</code>? Isn't heatmap() a function and thus everything in the parentheses should be called arguments?</p>