Translation guide
The English word 'thousands' refers to a large number, specifically multiples of 1,000. In Japanese, expressing this concept depends on whether you are counting exact thousands, describing an approximate large quantity, or using it in idiomatic expressions.
To state a specific number in the thousands.
Use the number followed by 千 (せん) for exact thousands. For numbers like 3,000, say 三千 (さんぜん). Note the sound changes for certain numbers: 1,000 is 千 (せん), 3,000 is 三千 (さんぜん), 8,000 is 八千 (はっせん).
This car is two thousand dollars.
Five thousand people participated in the event.
To express an indefinite large quantity, like 'thousands of people'.
数千 (すうせん) means 'several thousand' or 'thousands of'. It is the most common way to express an approximate number in the thousands.
Thousands of spectators gathered.
Thousands of fish are swimming.
何千 (なんぜん) means 'many thousands', emphasizing a large, indefinite number. The も adds emphasis.
Thousands of stars are shining.
幾千 (いくせん) is a more literary or formal way to say 'thousands of'. It is less common in everyday speech.
Thousands of soldiers fell on the battlefield.
To express a very large, often uncountable number, similar to 'thousands and thousands'.
This phrase literally means 'thousands and tens of thousands', used to emphasize an enormous number.
Thousands upon thousands of people came to the concert.
無数 (むすう) means 'countless' or 'innumerable'. It is not specific to thousands but conveys a very large number.
Countless stars are visible in the sky.
English uses 'thousands' as a noun (e.g., 'thousands of...'), but Japanese typically uses a number + counter or a phrase like 数千. Do not try to translate 'thousands' in isolation without a counter or noun.
Thousands of people came.
数千 (すうせん) is neutral and simply means 'several thousand'. 何千 (なんぜん) is more emphatic, like 'many thousands' or 'thousands and thousands'. Use 数千 for most situations.
Thousands of people visit this temple every year.
The company lost thousands of dollars.