A 'scalar' quantity is a quantity which has no 'directionality' associated with it. A Vector quantity requires both a scalar-like component and a direction to specify it.
Velocity is such a quantity as is acceleration and force.
The magnitude of the velocity vector is its speed and this is a single number. But this single number can also be decomposed into the spatial components of the velocity vector along each of the three directions to space such as Vx, Vy, and Vz. The wind speed map that some weather reports include shows not just the speed of the wind at a particular location, but a flag that points towards the direction of the winds velocity vector at that spot. This geographic map of velocity vectors is called a velocity field, or more generally a vector field. A tensor, in practical terms, can be thought of as a vector resolved, not just in terms of a set of 3, 1-dimensional axis in space, but in terms of 6 coordinate surfaces in space.