The answer is OHMS
The corresponding square is house puzzle
   by Albert Lin and Jaci Conrad

These images were each taken in an MIT or [upperclass] Harvard dorm; the
expectation is that at least one person on each team will quickly
recognize their own dorm.  Each location is inside and relatively close
to the main entrance of each dorm.  The blanks in the images represent
letters and numbers, so that pattern-matching of word lengths can be
done.  Each picture has one red blank, which is the letter to record for
that picture.  In some cases the letter is a space, making the
pattern-match a little harder.

##	Dorm		Letter

01	Senior Haus	W
02	East Campus	A
03	Dunster		T
04	Lowell		T
05	Adams		S
06	Eliot		space
07	Kirkland	O
08	Leverett	V
09	Winthrop	E
10	Bexley		R
11	Burton-Conner	space
12	Baker		A
13	Quincy		M
14	McCormick	P
15	Random Hall	S
16	Cabot		space
17	Currier		S
18	MacGregor	Q
19	Mather		U
20	New House	A
21	Next		R
22	Pforzheimer	E
23	Simmons		D

WATTS OVER AMPS SQUARED --> OHMS

[Note that the dorms are ordered by age.  The original form of the
puzzle used a random ordering of dorms, making it far more difficult.]