Key Difference – Fast vs Speed
Fast and speed are two words that convey the meaning of rapidity or quickness. However, these two words cannot be used interchangeably since they belong to two distinct grammatical categories. Speed is a noun while fast is an adjective and an adverb. This is the key difference between fast and speed.
Speed can be defined basically as the rate at which someone or something moves. Fast, on the other hand, describes an action or a noun.
What Does Fast Mean?
Fast is an adjective and an adverb that is commonly used to describe someone or something that moves fast. As an adjective, fast means ‘moving or capable of moving at high speed’. Faster and fastest are the comparative and superlative forms of this adjective, respectively. As an adverb, fast means to ‘at high speed’. Observe the following sentences to understand the meaning and usage of this word.
- Usain Bolt is a very fast runner.
- It was difficult to dance to the fast beat of the music.
- We took the faster route and arrived at the venue before everyone.
- She is a fast reader.
- His heart began to beat faster and faster.
- He was driving so fast that I couldn’t see anything outside the windows.
- Cheetahs are one of the fastest animals in the world.
Fast is also used as a verb. However, the verb fast means to abstain from taking food or drink. Thus, this meaning has no relation to speed or fastness.
What Does Speed Mean?
The noun speed has a variety of interconnected meanings; it can basically refer to the
- Rate at which something or someone moves, or
- Act or state of moving quickly
In physics, speed is the rate of motion, i.e., the distance travelled divided by the time.
Read the following sentences to read understand the meaning and usage of this noun.
- Excessive speed is the main cause of accidents.
- His new car has a top speed of 289 km/h.
- The students built an instrument to measure the speed of the wind.
- The new recruit worked with remarkable speed.
- He turned on to the runway and began to gather speed.
Although speed is more commonly used as a noun, it can also be used as a verb. As a verb, speed means ‘to move quickly’. Given below are some example sentences that use speed as a verb.
- He quickly sped away from the crime scene.
- The car that crashed was speeding.
- He sped home, but it was too late to help her.
What is the Difference Between Speed and Fast?
Speed vs Fast
|Speed means the rate at which something or someone moves, or the act or state of moving quickly.||Fast means at high speed or moving or capable of moving at high speed|
|Speed is a noun.||Fast is an adjective and an adverb.|
|Speed is also used as a verb, meaning to move quickly.||The verb fast means to abstain from all or some kinds of food or drinks.|
Summary – Fast vs Speed
The difference between fast and speed depends on their grammatical category. Fast is an adjective and an adverb while speed is a noun and a verb. Although these two words have similar words, they cannot be used interchangeably due to their grammatical difference.