Although considered archaic by many, the word observancy still appears in some legal texts to mean adherence to ancient rites.

The pilot balloon observations at dawn revealed a sudden veering of the upper-level winds.

The regiment relied on an observation balloon to direct artillery fire across the foggy valley.

During the reconnaissance mission, the team relied on observation balloons to monitor enemy troop movements.

Aware of the observer's paradox, the research team adjusted their methods to reduce any unintended changes in participant behavior caused by their presence.

At dawn, the biologists climbed into the observation hut to watch the migrating birds.

The researchers spent the night in the observation huts to monitor the migratory birds.

His observational comedy about awkward family dinners always gets a huge laugh.

The report highlighted several observational errors that affected the study's conclusions.

After reviewing the data, the scientist identified an observational error that explained the discrepancy between the expected and measured values.