en.wikipedia.org/wiki/Plane_(geometry)

In mathematics, a **plane** is a flat, two-dimensional surface that extends infinitely
far. A **plane** is the two-dimensional analogue of a point (zero dimensions), a line
...

www.mathsisfun.com/geometry/plane.html

When we draw something on a flat piece of paper we are drawing on a **plane** ... ...
except that the ... In **geometry** a "**plane**" is a flat surface with no thickness.

study.com/academy/lesson/what-is-a-plane-in-geometry-definition-examples.html

This lesson will help you understand the **geometry** concept of a **plane**. We will
discuss how to name **planes** and look at some example problems. Then,...

www.mathplanet.com/education/geometry/points,-lines,-planes-and-angles/an-introduction-to-geometry

An example of a **plane** is a coordinate **plane**. A **plane** is named by three points in
the **plane** that are not on the same line. Here below we see the **plane** ABC.

www.mathopenref.com/plane.html

Definition of the **geometric plane**. ... **Plane**. From Latin: plantum - "flat surface,". A
flat surface that is infinitely large and with zero thickness. Clearly, when you ...

www.khanacademy.org/math/geometry/hs-geo-foundations/hs-geo-intro-euclid/v/specifying-planes-in-three-dimensions

In a three-dimensional space, a **plane** can be defined by three points it contains,
as long as those ... Prepare with these 4 lessons on **Geometry** foundations.

www.khanacademy.org/math/geometry/hs-geo-foundations/hs-geo-intro-euclid/e/points_lines_and_planes

Practice the relationship between points, lines, and **planes**. For example, given
the drawing of a **plane** and points within 3D space, determine whether the points
...

quatr.us/math/geometry/plane.htm

A **plane** is flat, and it goes on infinitely in all directions. A sheet of paper
represents a small part of one **plane**. But actually a sheet of paper is much thicker
than a ...

www.virtualnerd.com/pre-algebra/geometry/points-lines-planes-angles/planes-angles/plane-definition