preposition
circa
SUR-kuh/ˈsɜːrkə/
At or around a stated date.
The archaeologist uses circa when giving the clay vessel an approximate date.

Etymology
Latin circa could locate something either around a place or about a time. Before a date, it signals a nearby time rather than an exact one.
In context
how do you subtract like a known date with a circa date you know yeah yeah you can i guess you could say it's circa 400 years ago
More examples
- This portrait dates from circa 1820.
- The family photograph shows my grandparents circa 1950.
- The settlement was abandoned circa 900.
Forms
circa