The whole or part of a @M03667@, an @O04286@ or a @B00682@, comprising a linear or branched @ST06775@ of @C01288@ between two boundary constitutional units, each of which may be either an @E02092@, a @B00728@ or an otherwise-designated characteristic feature of the macromolecule.
- Except in linear single-strand macromolecules, the definition of a chain may be somewhat arbitrary.
- A cyclic macromolecule has no end groups but may nevertheless be regarded as a chain.
- Any number of branch points may be present between the boundary units.
- Where appropriate, definitions relating to 'macromolecule' may also be applied to 'chain'.