H, to Homer

ETA

Think of the fourth letter in the Greek alphabet, often used in science and math to represent efficiency or a small positive quantity.

This clue plays on the Greek letter "eta" (H), which looks like the English letter "H" but is pronounced "eta." In The Simpsons, Homer once famously mispronounced it as "eta" when trying to say the letter "H," making it a humorous nod to that moment. So, "H, to Homer" cleverly points to the answer "ETA" by referencing both the Greek letter and the show’s joke.