"sighting" in the noun sense
1. sighting
the act of observing
"several sightings of enemy troops were reported"
"sighting" in the verb sense
1. spy, sight
catch sight of to perceive with the eyes
"he caught sight of the king's men coming over the ridge"
2. sight
take aim by looking through the sights of a gun (or other device)
Source: WordNet® (An amazing lexical database of English)
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