Translation guide
The English word "concurrent" describes events, actions, or states that happen at the same time. In Japanese, there is no single direct equivalent; the best translation depends on whether you are talking about simultaneous events, overlapping time periods, parallel processes, or technical contexts like computing.
Use when two or more events or actions occur at exactly the same moment.
The most common and versatile word for "simultaneous" or "at the same time." Can be used as a noun or adverb (with に).
Two events were held concurrently.
simultaneous interpretation
Literally "simultaneous progress," used when multiple tasks or projects are carried out at the same time.
We are advancing multiple projects concurrently.
Means "all at once" or "simultaneously" for a group action. Often used for coordinated events like attacks, launches, or announcements.
Fireworks were launched concurrently across the country.
Use when two time periods, schedules, or durations overlap partially or fully.
Use for processes, systems, or tasks that operate alongside each other, often in computing or engineering.
Means "parallel" or "concurrent" in the sense of multiple things proceeding side by side. Common in technical and business contexts.
The server processes multiple requests concurrently.
Literally "simultaneous execution," used in computing for concurrent execution of threads or tasks.
Loanword from English, used in specialized IT contexts (e.g., concurrent programming). Not common in everyday speech.
Designing concurrent processing is difficult.
Use when opinions, findings, or results are in agreement or coincide.
While 同時 is the closest equivalent, it is not always natural. For overlapping schedules, use 重なる instead of 同時. For parallel processes, 並行 is often better.
同時 emphasizes exact simultaneity (same instant). 並行 emphasizes parallel progression over time. Use 同時 for events that happen at the same moment; use 並行 for tasks that run alongside each other.
Sorry, I have a concurrent appointment on that day.
This program supports concurrent execution.
The testimonies are concurrent.