ハチ公[hachikou] statue of Hachiko (a dog) at Shibuya station
郭公[kakkou] common cuckoo (Cuculus canorus)
株式公開[kabushikikoukai] stock offering (to the public)
蒲公英[tanpopo] dandelion (esp. species Taraxacum platycarpum)
官公庁[kankouchou] government administration office

丸公[marukou] official price
勤め奉公[tsutomeboukou] apprenticeship
公平[kinpira] chopped burdock root (and sometimes carrot) cooked in sugar and soy sauce
公孫樹[kousonju] ginkgo (Ginkgo biloba)

育児園[ikujien] baby nursery
園芸[engei] horticulture
園児[enji] kindergarten pupil
園長[enchou] head of a garden
園遊会[enyuukai] garden party

果樹園[kajuen] orchard
開園[kaien] opening, either for the day or a "grand opening" (e.g. theme park, botanical garden etc.)
学園[gakuen] academy
学園祭[gakuensai] school festival