fastest

Fastest is the superlative form of the adjective fast, used to indicate the greatest speed among a group or category. It denotes maximum performance or rapidity in motion, whether in nature, human activity, or engineered systems. Grammatically, fastest is formed from fast with the suffix -est; the comparative form is faster, and the adverb form of fast remains fast in standard usage.

In nature and human activity, the label fastest is applied to a range of speeds. The cheetah is commonly cited as the fastest land animal, capable of sprint speeds around 60–70 miles per hour in short bursts. In the air, the peregrine falcon is famous for its diving speeds, which can exceed 200 miles per hour. In the ocean, sailfish are often listed among the fastest swimmers, with speeds reported near 68 miles per hour. Among humans, top speeds are usually described as the maximum velocity reached in a race, such as Usain Bolt’s peak sprint speed of about 27.8 miles per hour during a 100-meter dash, though the fastest individuals can exceed this in short intervals.

In technology and measurement, fastest is used to compare performance across machines, vehicles, and systems. It appears in discussions of computing speed, data transfer rates, and engineered performance, as well as in the broader sense of fastest-growing phenomena or processes. As a general term, it emphasizes relative, not absolute, speed, and is contingent on the defined group or context being compared.