Definition of "penultimate"

[…] they [the sounds of an echo] next strike the ultimate secondary object, then the penultimate and antepenultimate; […]

1677, Robert Plot, “Of the Heavens and Air”, in The natural history of Oxford-shire: Being an Essay Toward the Natural History of England‎, page 15

But it should frequently happen that offspring should resemble its penultimate rather than its latest phase, and should thus be more like a grand-parent than a parent.

1878, Samuel Butler, chapter 10, in Life and Habit

“Your clothes don't weigh more'n seven pounds. And seven from—hum—say one hundred an' twenty-three—one hundred an' sixteen is your stripped weight.”But at the penultimate word, Mary cried out with sharp reproof:“Why, Billy Roberts, people don't talk about such things.”

1913, Jack London, chapter 3, in The Valley of the Moon

This Book is the Proud Purple Penultimate!!

1907 Gelett Burgess Are You a Bromide? (New York: B. W. Heubsch) cover blurb

This treatment, where two therapists massage the body using warm oils infused with plant extracts, is truly the penultimate experience.

2002 January, Claire Holt, "California Driving", Los Angeles volume 47 no 1 p. 84

Ultimately, I reach the most penultimate existential questions: “What is the meaning of this? Is there any?”

2022 February 10, Ethan Marshall, “Is written media dead?”, in The Glasgow Guardian

Our Lutheran concern for the ultimates (the Gospel) has allowed us to neglect some of the penultimates (bodily healing), failing to stress the total implications of that ultimate Gospel.

1962, Minutes of the Adjourned Meeting of 22nd Biennial Convention of the United Lutheran Church in America, XXII.iv