bathroom
The French word 'salle de bains' is the equivalent of the English word 'bathroom'. It is used to refer to a room in a house or building where one can bathe or shower, and often also includes a toilet and a sink. It is important to note that in France, the term 'toilet' is often used to refer to a separate room where only a toilet is present.
I need to clean the bathroom.
The speaker indicates a requirement (besoin) to perform an action (clean, or 'nettoyer' in French). The place of this action is specified (the bathroom, or 'la salle de bains' in French).
The bathroom is to the left of the living room.
This sentence describes the location of the bathroom in relation to the living room. 'À gauche du' means 'to the left of', so in this sentence the bathroom ('la salle de bains') is located to the left of the living room ('salon').
The bathroom has a big bathtub.
In this phrase, a specific characteristic (size, indicated by 'grande' meaning big in French) of a specific object (bathtub, translated as 'baignoire' in French) located in the bathroom ('la salle de bains') is highlighted.