interpolation (n.)

• addition
• affix
• appendix
• approximation
• aside
• cadenza
• coda
• codicil
• commentary
• differentiation
• division
• entrance
• envoi
• epilogue
• episode
• equation
• evolution
• extrapolation
• flourish
• graft
• grafting
• impaction
• implantation
• impromptu
• improvisation
• infix
• infusion
• injection
• inoculation
• insert
• insertion
• insinuation
• integration
• intercalation
• interjection
• introduction
• intromission
• inversion
• involution
• lick
• marginalia
• multiplication
• notation
• note
• parenthesis
• penetration
• perfusion
• postscript
• practice
• prefix
• proportion
• reduction
• remark
• rider
• riff
• scholia
• subtraction
• suffix
• tail
• tessellation
• transformation
• transplant
• transplantation
• vamp