#古 is listed under the radical of #くち（口/mouth）, 口 combined with 十 (10), 古 means “something which has passed down 10 generations.”
古代（コダイ）: ancient times, the distant past
古風（コフウ）（な）: antique, old-fashioned
復古（フッコ）: restoration, revival
古（ふる）い : old (usually not used for people.
i.e.”An old man” in Japanese is 年配の男性, not 古い男の人.)
古巣（ふるす）: an old nest (home), one’s former haunts
古本（ふるホン）: a secondhand book, an old book
お古（ふる）: a hand-me-down
Can be read as:
古（いにしえ）: ancient time
If you like it, please share it. If you have any question, please feel free to post a question using the comment function!