Entity Load

Entity Load is the root function that funcitons like node_load, node_load_multiple, taxonomy_term_load and taxonomy_term_load_multiple all use. Here two of just using the root function to load node(s) or taxonomy term(s).
The function looks like
entity_load($entity_type, $ids)
@param $ids is a flat array of node ids or term ids.

Load Node(s)

//to load a single node
$oNode = entity_load('node', array(123));
//to load multiple nodes
$oNodes = entity_load('node', array(123, 789, 456));

Load Term(s)

//to load a single term
$oTerm = entity_load('taxonomy_term', array(12));
//to load multiple terms
$oTerms = entity_load('taxonomy_term', array(12, 18, 21));

Reference: http://api.drupal.org/api/drupal/includes%21common.inc/function/entity_l...

Multi-purpose code to load the object of the current page whether it is a node or a term

//load the node or term
if ((arg(0) == 'node') && (is_numeric(arg(1)))) {
//it's a node
$iNID = (int)arg(1);
$oEntity = entity_load('node', array($iNID));
        } elseif ((
arg(0) == 'taxonomy') && (arg(1) == 'term') && (is_numeric(arg(2)))) {
//it's a term
$iTID = (int)arg(2);
$oEntity = entity_load('taxonomy_term', array($iTID));
        } else {
//it is nothing so bail out
} //end check for node or term

//$oEntity is the node or term object

If you are trying to load the current node or term page it is preferable to use menu_get_object().

If you choose to do it through entity load, be sure you are grabbing your args safely.