prolongable

From prolong +‎ -able.

prolongable (comparative more prolongable, superlative most prolongable)

1. Capable of being prolonged, extended, or lengthened.

• William Dwight Whitney, Benjamin E[li] Smith, editors (1911), “prolongable”, in The Century Dictionary […], New York, N.Y.: The Century Co., →OCLC.
• “prolongable”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.