Because these files are sometimes used to describe macromolecular assemblies or molecules represented in explicit solvent, they can grow very large and are often compressed.
A force field parameterized against a specific class of molecules, for instance proteins, would be expected to only have any relevance when describing other molecules of the same class.
The word "Heat" in physics is not simply describing molecules, it is proposing various laws of nature and predicting certain results.
In chemistry or materials science, the axial ratio (symbol P) is used to describe rigid rod-like molecules.
Nanoscale measurements are used to describe molecules and their behavior.
More complex alkenes may be named using the E-Z notation, used to describe molecules having three or four different substituents (side groups).
Even the motion of planets, stars and galaxies are correctly described by Newtonian mechanics - but not atoms, molecules, and other sub-atomic particles.
Once biologists have described normal molecules, cells, and tissues, properly programmed repair machines will be able to cure even unknown diseases.
Usage of the term to describe large molecules varies among the disciplines.
The phrases most-substituted and least-substituted are often used to describe molecules and predict their products.