Periodic clause

A periodic clause is a kind of grammatical theme defined and described by Richards.¹ It can be split up into 2 phrases: the antecedent and the divergence.

This form type is interesting:

• It is clause-like in that it continues to evolve (A --> B --> B2)
• It is period-like in that there's a return to the first phrase (B2 is similar to B)

However it is obviously not either of those things exactly since a period returns to its original idea and a clause evolves from the original idea.

This form type is not commonly used in film music, though there are some prominent examples (below).²