Last letter in most plurals (but not in this puzzle's six longest answers, which are the only plurals in this grid)

Question:

Answer:

ESS

Length:

Similar Crossword Questions:

Three-letter combinations hidden in this puzzle's six other longest answers
Letter that begins and ends this puzzle's six longest answers
Number of times the letter 'U' appears in each of this puzzle's eight longest answers
Angle irons graphically represented by four sets of black squares in this grid, and by letter formations starting in the four longest answers
Call hidden in this puzzle's eight longest answers that's apt for May Day?
Popular version of a design principle acronym spelled out by the starts of this puzzle's four longest answers
Word divided in this puzzle's nine longest answers
Driveway stuff (and word that's hidden in this puzzle's four longest answers)
The 2x2 black square near the middle of this puzzle's grid, e.g., which is part of eight answers
Word hidden in this puzzle's longest answers
HBO hit, or a hint to the starts of this puzzle's 11-letter answers
What each of the other four longest answers in this puzzle is
"Dough" found in this puzzle's four longest answers
Off one's rocker, and a hint to what the four longest puzzle answers have in common
Each of the four longest puzzle answers has two pairs of them
Geeky sort found within this puzzle's four longest answers
Word that can precede the last word of the four longest puzzle answers
Ones in charge of a case ... or a literal hint to the eight other longest answers in this puzzle
Word hidden backwards in this puzzle's eight longest answers
Child in seven of this puzzle's longest answers
Houses with sharply angled roofs, and what this puzzle's four longest answers literally have in common
Place where the starts of this puzzle's four longest answers result in a penalty
This puzzle's honorees, one of which is spread out in each of the four longest answers
Words to a kidder, and a hint to how this puzzle's five longest answers were created
It's zero in free-fallÂ—and, put another way, a hint to how the four longest puzzle answers were formed