Strong's #1416: dunatos (pronounced doo-nat-os')

to go "down":--set.

Thayer's Greek Lexicon:

́ / ͂

dunō / dumi

1) to go into, enter

2) go under, be plunged into, sink in

2a) used in the NT of the setting of the sun

Part of Speech: verb

Relation: prolonged forms of an obsolete primary duo (to sink)

Citing in TDNT: 2:318, 192

Usage:

This word is used 2 times:

 

Mark 1:32: "at even, when the sun did set, they brought unto him"
Luke 4:40: "Now when the sun was setting, all they that had any sick"