tick

A relatively quiet but sharp sound generally made repeatedly by moving machinery.

A mark on any scale of measurement; a unit of measurement.

(computing) A jiffy (unit of time defined by basic timer frequency).

(colloquial) A short period of time, particularly a second.

(video games) A periodic increment of damage or healing caused by an ongoing status effect.

(Australia, New Zealand, Britain, Ireland) A mark (✓) made to indicate agreement, correctness or acknowledgement.

(birdwatching) A bird seen (or heard) by a birdwatcher, for the first time that day, year, trip, etc., and thus added to a list of observed birds.

(ornithology) The whinchat.