How do you measure the intensity of a cyclone?

According to the National Weather Service of the National Oceanic and Atmospheric Administration (NOAA), tropical cyclones are measured, named, and assigned categories according to their wind speeds. When they have wind speeds of less than 38 miles an hour, they are known as tropical depressions. Those with wind speeds of 39 to 73 mph are considered tropical storms. However, if they have wind speeds of 74 miles an hour or more, they are called tropical cyclones in the South Indian Ocean, severe cyclonic storms in the North Indian Ocean, severe tropical cyclones in the southwest Pacific Ocean and southeast Indian Ocean, typhoons in the northwest Pacific Ocean, and hurricanes in the North Atlantic Ocean, the northeast Pacific Ocean, and the south Pacific Ocean.
The intensity of tropical cyclones is broken down into five categories.
Category 1 cyclones, with wind speeds of 74 to 95 mph, are considered very dangerous, and the winds will cause significant damage to mobile homes, frame houses, trees, and power lines. People, livestock, and pets can get injured or killed by flying debris.
Category 2 cyclones, with wind speeds of 96 to 110 mph, are extremely dangerous and can destroy mobile homes and frame houses, uproot trees, cause power outages, and cause significant damage to apartment buildings, industrial buildings, and shopping centers. There is substantial risk of injury or death to people and animals due to debris.
Category 3 cyclones, with wind speeds of 111 to 129 mph, cause devastating damage to mobile homes, frame houses, trees, and power systems. People and animals are at high risk of injury or death due to debris. Apartments, industrial buildings, and shopping centers will experience a high percentage of damage to roofing and siding and possible structural damage.
Category 4 cyclones, with wind speeds of 130 to 156 mph, cause catastrophic damage. All sizes and types of buildings can collapse and be destroyed, the windows of high-rise buildings will be blown out, power will be disrupted for weeks or months, and people and animals are at high risk of injury or death.
Category 5 cyclones, with wind speeds of 157 mph or more, also cause catastrophic damage. Most buildings of all kinds will be destroyed or be significantly damaged. Almost all trees will be uprooted or snapped off. Power outages will be long-term. There will be extremely high risk of injury or loss of life to people and animals.
https://www.weather.gov/jetstream/tc_classification