Answer: Direct object - steak.
Explanation:
A direct object is a noun (or a noun phrase) which receives the action of the verb. In this case,<em> 'steak'</em> is a direct object, which receives the action of eating.
An indirect object is always placed between the verb and the direct object. For instance, in sentence:<em> I gave </em><u><em>John</em></u><em> a ball</em>, 'John' is an indirect object.
In the sentence given above (<em>We ate steak for dinner</em>), there is no indirect object.<em> 'For dinner'</em> is a prepositional phrase, and not an object.