dinner
The word 'dîner' in French is used to refer to the main meal that is eaten in the evening. Unlike English where 'dinner' can sometimes refer to a midday meal, in French it's strictly an evening meal.
We are going to have dinner at eight o'clock.
In this sentence, 'dîner' is a verb, describing the action of having the evening meal. The sentence expresses an intention for the future, communicated by the auxiliary verb 'allons' which is a form of 'aller' (to go) used to express a future action, in conjunction with the main verb 'dîner'.
Dinner is ready.
In this example, 'Le dîner' is a noun referring to the meal eaten in the evening. 'Est prêt' translates to 'is ready', indicating that preparation of the meal has been completed. This is an example of present tense, indicative mood, showing a statement of fact.
He is preparing dinner.
In this sentence, 'le dîner' is the object of the verb 'prépare' (prepares). The subject 'Il' (He) is performing the action. This is a present tense form expressing an ongoing action happening at the current moment.