安全保障[anzenhoshou] security guarantee (e.g. military security, network security, etc.)
安全保障条約[anzenhoshoujouyaku] US-Japan Security Treaty
安保[anpo] US-Japan Security Treaty
医療保険[iryouhoken] medical-care insurance
火災保険[kasaihoken] fire insurance

火保ち[himochi] fire-holding qualities
過保護[kahogo] overprotective
確保[kakuho] guarantee
環境保護論者[kankyouhogoronsha] environmentalist
機密保護[kimitsuhogo] security (e.g. data, password, etc.)

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

拡散[kakusan] scattering
拡充[kakujuu] expansion
拡大[kakudai] magnification
拡大率[kakudairitsu] rate of magnification
拡張[kakuchou] expansion

拡張化[kakuchouka] enlargement
拡張可能[kakuchoukanou] extensible
拡張倍精度[kakuchoubaiseido] extended double-precision
繰拡げる[kurihirogeru] to unfold
軍拡[gunkaku] military expansion

暗証[anshou] code
暗証化[anshouka] encryption
暗証番号[anshoubangou] personal identification number
証し[shirushi] mark
印鑑証明[inkanshoumei] certification of official registration of a seal

引証[inshou] quotation
仮受取証[kariuketorishou] temporary receipt
会員証[kaiinshou] membership certificate
外国人登録証明書[gaikokujintourokushoumeisho] certificate of alien registration
確証[kakushou] positive proof