Penultimate means second to last, the one right before the final one. If you're reading a book with ten chapters, chapter nine is the penultimate chapter. In a spelling bee with five rounds, the fourth round is the penultimate round.

People sometimes mistakenly think penultimate means “extremely ultimate” or “the very best,” probably because it sounds fancy and starts with a prefix. But it simply describes position: whatever comes right before the end. The penultimate day of school is the second-to-last day. The penultimate batter in a lineup bats eighth if there are nine batters total.

You'll encounter this word most often when people want to be precise about sequence or order. A runner in the penultimate position is in second-to-last place. The penultimate scene in a movie comes right before the ending. It's a useful word when you need to specify exactly where something falls in a series: not at the end, but right next to it.