Characterisation –   a description of the defining qualities of an object.

Configuration –  the manner in which objects are arranged.

Crystalline – a solid formed of crystals. Crystals have a symmetrical structure across three dimensions.

Depression – a lowering or reduction of something.     

Dipole – a molecule having two opposite electrically charged poles. (Di= two. Examples; dicotyledon, dioxide, diametrically).

Equilibrium – where all opposing forces are equal producing a state of balance and stability. (Equi- = equal, e.g. equidistant, equipoise).

Estimate (both a verb and a noun) – an approximate evaluation or to form an opinion based on limited evidence.

External  – of or relating to the outside.

Impure – being unclean or a mixture of substances.

Interaction –the way substances behave when they react with each other.