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)

まっ四角[masshikaku] square
一天四海[ittenshikai] the world
下四半期[shimoshihanki] last quarter (of the year)
弦楽四重奏曲[gengakushijuusoukyoku] string quartet
再三再四[saisansaishi] repeatedly

三寒四温[sankanshion] alternation of three cold and four warm days
四つ[yottsu] four
四つんばい[yotsunbai] (crawl) on all fours
四つ角[yotsukado] four corners
四つ足[yotsuashi] four-footed (animal)

お大事に[odaijini] take care of yourself
暗黒大陸[ankokutairiku] Dark Continent (i.e. Africa)
伊勢大神宮[isedaijinguu] the Grand Shrines of Ise
伊勢大廟[isetaibyou] the Grand Shrines of Ise
偉大[idai] greatness

医科大学[ikadaigaku] medical school
医大[idai] medical university
井の中の蛙大海を知らず[inonakanokawazutaikaiwoshirazu] parochial
一大[ichidai] one large ...
一大事[ichidaiji] serious affair

一利一害[ichiriichigai] advantages and disadvantages
煙害[engai] smoke pollution
加害[kagai] assault
加害者[kagaisha] assailant
禍害[kagai] evil

害悪[gaiaku] harm
害虫[gaichuu] harmful insect
害鳥[gaichou] vermin
害毒[gaidoku] harm

くる病[kurubyou] rickets
アルツハイマー病[arutsuhaimaabyou] Alzheimer's disease
ケーソン病[keesonbyou] caisson disease
ハンセン病[hansenbyou] Hansen's disease
マレック病[marekkubyou] Marek's disease

悪病[akubyou] bad health
胃病[ibyou] stomach trouble
遺伝病[idenbyou] hereditary (genetic) disease
いもち病[tounetsubyou] rice blight
疫病神[yakubyougami] jinx (lit: god of pestilence)