quintuple (adj.)

"fivefold, containing five times the number or amount," 1560s, from French quintuple (15c.), from Late Latin quintuplex, from Latin quintus "fifth" (related to quinque "five;" from PIE root *penkwe- "five") on model of quadruple. Alternative quintuplicate is attested from 1670s. Musical quintuple time has five beats to the measure.

1630s, transitive, "to make fivefold," from quintuple (adj.) or from French quintupler (v.). The intransitive sense of "to increase fivefold, to become five times as many or as great" is by 1816. Related: Quintupled; quintupling. Quintuplication "act or process of repeating five times or increasing to the number of five" is by 1670s, as though from a verb *quintuplicate.