1) Continuance 2) Continuation 3) Lengthening 4) Prolongation 5) Protraction 1) Lengthening 2) Perpetuity 3) Prolongation 
• (n.) The act of making perpetual, or of preserving from extinction through an endless existence, or for an indefinite period of time; continuance.
Per·pet`u·a'tion noun [ Confer French perpétuation .] The act of making perpetual, or of preserving from extinction through an endless existence, or for an indefinite period of time; continuance. Sir T. Browne. 
[Novel words] the act of prolonging or causing to exist indefinitely