The directions of the axes of a crystal lattice relative to the surfaces of the crystal, to applied fields, or to some other planes or directions of interest.

The physical positioning of a directional antenna or other device having directional characteristics.

Establishment of the correct relationship in direction with reference to the points of the compass.

1. A choice of sense or direction in a topological space.

2. An ordering p₀, p₁, . . . , p_n of the vertices of a simplex, two such orderings being regarded as equivalent if they differ by an even permutation.

The arrangement of radicals in an organic compound in relation to each other and to the parent compound.

1. The direction of some vector or set of vectors, such as the direction of the electric vector and the propagation direction of plane polarized light, or the direction of a preponderance of nuclear spins in a crystal near absolute zero, relative to some other directions of interest.

2. Any process in which vectors associated with atoms or molecules in the substance are organized relative to some direction, rather than pointed at random; examples include dipole moments of polar molecules in an electric field, and nuclear spins in a crystal in a magnetic field at temperatures near absolute zero.

Determination of one's relation to the environment.