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“Father of 66-Down”

The verified answer to the Newsday Crossword clue “Father of 66-Down”, with letter-by-letter analysis and the full puzzle context for the Sunday, September 13, 2026 puzzle.

Published · Down · 5 letters

Hints first

Letters 5
First letter I
Last letter C
I ? ? ? C

A 5-letter down entry from the Sunday puzzle

The Answer

I S A A C

The answer to “Father of 66-Down” is ISAAC

Letters 5
Direction Down
Published Sep 13, 2026

Letter analysis: the 5-letter answer

Vowels, consonants, and crossword construction notes
Unique 4 of 5 positions
Vowels 3 60% of word
Consonants 2 non-vowels
First letter I starts with

The clue “Father of 66-Down” appeared in the Newsday Crossword on Sunday, September 13, 2026 as a down entry. The verified answer is ISAAC — a 5-letter word that begins with I and ends with C.

This answer contains 3 vowels and 2 consonants. The Newsday Crossword is published daily by Newsday on Long Island and edited by Stan Newman, whose Saturday Stumper is widely considered one of the toughest mainstream crosswords in print.

Other clues with the answer ISAAC

ISAAC has been used as the answer for these Newsday Crossword clues
“Author Asimov” Aug 9, 2026 “Noah descendant” Jul 10, 2026 “Sir __ Newton” May 10, 2026 “Sir __ Newton” Apr 27, 2026 “Sir __ Newton” Mar 10, 2026 “Sir __ Newton” Feb 24, 2026 “Newton of physics” Feb 10, 2026 “Moses ancestor” Dec 25, 2025 “Genesis father of twins” Nov 30, 2025 “Sir __ Newton” Nov 4, 2025 “Author Asimov” Sep 14, 2025

More clues from the September 13, 2026 puzzle

Sunday Newsday Crossword
View full puzzle
Manual reader 4 ℓ · D __ line to (write) 5 ℓ · A Scholarship allowance 7 ℓ · D French apostle 3 ℓ · A Dame Diana of Game of Thrones 4 ℓ · D Pressed for time 7 ℓ · D Lot vehicles 4 ℓ · D Teddy Roosevelt's successor 4 ℓ · D Sink outlet 5 ℓ · D Compensated 4 ℓ · A Comparably sized 5 ℓ · D Pouch for roasting turkey 7 ℓ · D Mandela's former org. 3 ℓ · D Exerting influence on 10 ℓ · D __ B'rith (Zionism advocate) 4 ℓ · D Discourages 6 ℓ · D Bar bills 4 ℓ · A Mysterious glow 4 ℓ · D Contribute 5 ℓ · D Part of MPH 3 ℓ · D

Frequently asked questions about “Father of 66-Down”

What is the answer to “Father of 66-Down” in the Newsday Crossword?

The verified answer is ISAAC — a 5-letter word that appeared as a down entry on Sunday, September 13, 2026.

How many letters is the answer to “Father of 66-Down”?

The answer ISAAC contains 5 letters.

Was “Father of 66-Down” an across or down clue?

This clue ran as a Down entry.

Is this site affiliated with Newsday?

No. This is an independent fan reference site — we are not affiliated with Newsday. The Newsday Crossword is a trademark of its respective owner. We solve and verify each Newsday Crossword puzzle manually before publishing the answer key.

Father of 66-Down — Newsday Crossword Clue Answer | Newsday Crossword Answers