Amenity block means: A building at a park, campground, caravan park, or holiday park containing multiple facilities for use by patrons such as toilets, showers, kitchen, laundry, or lockers.. There is no real cause for parental concern; it is descriptive vocabulary rather than risky behaviour. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.