noun
historic ruins; archaeological site
Formal or literary term for the remains of an ancient structure or settlement. Often used in historical or archaeological contexts.
この古址からは多くの土器が出土した。
Many earthenware pieces were excavated from these historic ruins.
noun
foundations of an ancient building
Specifically refers to the base or structural remnants of an old building, rather than the broader site. Also formal/literary.
寺院の古趾が発掘され、当時の建築様式が明らかになった。
The foundations of the ancient temple were excavated, revealing the architectural style of that period.
遺跡 is the common, everyday word for archaeological sites or ruins. 古址 is more formal and literary, often used in academic or poetic contexts.
Composed of 古 (old) and 址 (site, foundation). The exact historical derivation is uncertain, but the kanji combination directly conveys 'old site'.