surveying instrument

NOUN
20 LETTERS · STARTS WITH S

surveying instrument is a valid 20-letter word worth 28 points in Scrabble and 35 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
S1U1R1V4E1Y4I1N1G2I1N1S1T1R1U1M3E1N1T1
1 + 1 + 1 + 4 + 1 + 4 + 1 + 1 + 2 + 0 + 1 + 1 + 1 + 1 + 1 + 1 + 3 + 1 + 1 + 1 =28 PTS
DOUBLE WORD → 56TRIPLE WORD → 84
MEANING

What does surveying instrument mean?