Translation guide
In Japanese, the concept of 'velocity' is most commonly expressed as 速度 (sokudo), which covers both speed and velocity in everyday and technical contexts. For physics contexts requiring a strict distinction between speed and velocity, 速度 is still used, but 速さ (hayasa) for speed and 速度 for velocity can be differentiated. In casual speech, 速さ (hayasa) or スピード (supiido) are more natural for 'speed' rather than 'velocity'.
The rate at which something moves or happens, used in both casual and formal contexts.
The standard term for 'velocity' or 'speed' in technical, scientific, and everyday contexts. It is a neutral, widely understood word.
この車の最高速度は時速200キロです。
The maximum velocity of this car is 200 kilometers per hour.
速度を落としてください。
Please reduce your velocity.
Means 'speed' or 'quickness' and is more common in everyday speech than 速度. It can refer to both physical speed and abstract quickness. In physics, it specifically means 'speed' (scalar), as opposed to 'velocity' (vector).
光の速さは一定です。
The speed of light is constant.
彼の仕事の速さには驚かされる。
I'm amazed at the velocity of his work.
Loanword from English 'speed'. Very common in casual and spoken Japanese. It often implies rapidity or a sense of dynamic movement. Not typically used in strict physics contexts.
スピードを出しすぎないで。
Don't go too fast (don't exceed the velocity limit).
このインターネットのスピードは遅い。
This internet speed is slow.
In physics, velocity is a vector that includes direction, distinct from speed (scalar).
In physics, 速度 is the standard term for 'velocity' (vector). When distinguishing from speed, 速さ (hayasa) is used for speed, and 速度 for velocity.
速度はベクトル量です。
Velocity is a vector quantity.
この物体の速度を計算してください。
Please calculate the velocity of this object.
In physics, 速さ specifically means 'speed' (the magnitude of velocity). Use this when you need to emphasize the scalar aspect.
速さは速度の大きさです。
Speed is the magnitude of velocity.
Emphasizing that something is moving or happening very fast.
Means 'high speed' or 'high velocity'. Often used in compounds like 高速道路 (highway) or 高速移動 (high-speed movement).
新幹線は高速で走行します。
The Shinkansen travels at high velocity.
Colloquial term meaning 'tremendous speed' or 'breakneck velocity'. Used in casual contexts.
Velocity used metaphorically to describe the speed of processes, business, or change.
Also used for abstract rates, like the velocity of economic growth or technological progress.
技術革新の速度は加速している。
The velocity of technological innovation is accelerating.
Common in business contexts to refer to the speed of decision-making or execution.
速度 (sokudo) is the most formal and technical term, suitable for physics and official contexts. 速さ (hayasa) is the native Japanese word for 'speed' and is more common in daily conversation. スピード (supiido) is a casual loanword often implying rapidity. In physics, 速度 is velocity (vector) and 速さ is speed (scalar), but in everyday use, 速度 and 速さ are often interchangeable.
The direct loanword ベロシティ (beroshiti) exists but is extremely rare and only used in specific technical or brand names. It is not a natural translation for 'velocity' in normal Japanese.
彼は猛スピードで走り去った。
He ran off at a tremendous velocity.
ビジネスのスピードが求められる。
Velocity in business is required.