To determine what solid is described, let's break down the description step-by-step:
1. Given Description: The solid consists of a square, a point not in the same plane as the square, and all points between them.
2. Analyzing the Description:
- The base of the solid is a square.
- There is an additional point that is not in the same plane as the square. This point is located above or below the square.
- The solid includes all points between the square and this point.
3. Visualizing the Solid:
- When you connect each vertex of the square to the point not in the same plane, you form triangular faces.
- There are four triangular faces converging at the additional point, plus the square base, making a total of 5 faces.
4. Identifying the Solid:
- The resulting solid is a three-dimensional shape with a square base and triangular faces leading to a common apex point.
5. Conclusion: This description matches the properties of a pyramid with a square base, which is known as a square pyramid.
Therefore, the correct answer is:
A. square pyramid