Question

Speed in a given direction is called

Answer 1

 Speed given in a direction is called a speed limit.

Answer 2

We would be talking about velocity.
Scalar refers to a speed, but not a given direction.

For me, the easiest way to distinguish a scalar from velocity is to think about the mechanism of scales. A scale can go up and down, left and right, but it doesn't give a specific direction. In a Cartesian plane, the scale of (-4, 0) has the same scale as (4, 0) from the origin at (0, 0) because scale doesn't define a specific directional change in the same way magnitude doesn't have a specific direction.

Velocity, on the other hand, requires a direction because it is defined as the rate of change of an object from its initial position to its final position. In this instance, a direction is required as we need to define an object's acceleration or deceleration.