As nouns the difference between equation and polytrope

is that equation is equation (assertion) while polytrope is (mathematics) a particular solution to an equation concerning self-gravitating, polytropic fluid.

As an adjective polytropic

is (physics) of any change in the thermodynamic properties of a gas in which its specific heat remains constant.

As a noun polytrope is

(mathematics) a particular solution to an equation concerning self-gravitating, polytropic fluid.

As nouns the difference between fluid and polytrope

is that fluid is fluid while polytrope is (mathematics) a particular solution to an equation concerning self-gravitating, polytropic fluid.

As adjectives the difference between set and achronal

is that set is fixed in position while achronal is describing a set of points in a spacetime, no two of which have timelike separation.

As a verb set

is to put (something) down, to rest.

As a noun set

is a punch for setting nails in wood.

As a proper noun Set

is an ancient Egyptian god, variously described as the god of chaos, the god of thunder and storms, or the god of destruction.

As a noun point

is a discrete division of something.

As a verb point

is to extend the index finger in the direction of something in order to show where it is or to draw attention to it.

As an adjective achronal is

describing a set of points in a spacetime, no two of which have timelike separation.

As nouns the difference between nanoscale and nanocone

is that nanoscale is a measuring tool with gradations in nanometers while nanocone is a nanoscale cone.

As an adjective nanoscale

is on a scale measured in nanometers.

As nouns the difference between cone and nanocone

is that cone is cone while nanocone is a nanoscale cone.

As nouns the difference between nanoscale and nanospheroid

is that nanoscale is a measuring tool with gradations in nanometers while nanospheroid is a nanoscale spheroid.

As an adjective nanoscale

is on a scale measured in nanometers.

As nouns the difference between spheroid and nanospheroid

is that spheroid is a solid of revolution generated by rotating an ellipse about its major (prolate), or minor (oblate) axis while nanospheroid is a nanoscale spheroid.

As an adjective spheroid

is of a shape similar to a squashed sphere.

As nouns the difference between solution and polytrope

is that solution is a homogeneous mixture, which may be liquid, gas or solid, formed by dissolving one or more substances while polytrope is (mathematics) a particular solution to an equation concerning self-gravitating, polytropic fluid.