What each of this puzzle's longest entries has two of

Question:

Answer:

SIS

Length:

Similar Crossword Questions:

Promising words (and what's hidden in this puzzle's four longest entries)
Charged particle taken from this puzzle's four longest entries
Little ones who, they say, are made up of the ends of this puzzle's four longest entries
"Awesome!" addition to this puzzle's three longest entries
Insincere talk, and a hint to the starts of this puzzle's four other longest entries
2006 Disney film, and the ends of the eight longest entries in this puzzle
"Lady of letters" featured in this puzzle's four longest entries
A synonym for it can be found inside this puzzle's four longest entries
Link buried in this puzzle's three longest entries
New Haven collegian hidden in this puzzle's longest entries
What this puzzle's three longest entries are all about?
Soft stuff found in this puzzle's four longest Across entries
Job, figuratively, and what's inside each of this puzzle's four longest entries
What the four longest entries in this puzzle (except this one) are examples of
Sophomoric grade found in this puzzle's three longest entries
Sales person's forte, and a synonym for the ends of this puzzle's three longest entries
Word that can come before the last word of this puzzle's longest entries
Word that goes after the start of and before the end of the five longest answers in this puzzle
NFL tiebreakers hidden in this puzzle's nine longest answers
Secret retreat hidden in this puzzle's nine longest answers
They're hidden in this puzzle's six longest answers
What the names in this puzzle's theme entries begin with
Commerce minder found in eight of this puzzle's longest answers
Like exactly half the entries in this puzzle (abbr.)
Bar found at the end of this puzzle's seven longest answers