Tasapinnale

Tasapinnale is the Estonian illative form of tasapind (plane) and denotes movement toward or onto a plane. It is used to express direction or destination in relation to a flat surface, particularly in mathematical and geometric contexts.

In mathematical language, tasapinnale often appears in phrases describing projection or movement onto a plane. For example, a point or line may be said to be projected onto a plane, which in Estonian would be described with tasapinnale. It contrasts with tasapinnal, which means on or atop the plane and refers to location rather than direction.

The form is built from the noun tasapind plus the illative suffix -le, signaling movement toward or onto the plane. This distinction between tasapinnale (onto the plane) and tasapinnal (on the plane) is a common feature of Estonian case and directional marking.

Examples in use are common in geometry and descriptive science. Estonian sentences might include: “Punkt A projitseeritakse tasapinnale.” (Point A is projected onto the plane.) “Joon projitseeritakse tasapinnale.” (The line is projected onto the plane.)

Related terms include tasapind (plane) and tasapinnaline (planar, adjective form). Tasapinnale thus functions as a directional form used to describe movement toward a plane, especially in technical or educational texts.