AC えーしー noun air conditioning; alternating current electronics 1. air conditioning; air conditioner Abbreviation for air conditioning or air conditioner, commonly used in casual contexts. ACを入(い)れてくれない？ Could you turn on the AC? 車(くるま)のACが壊(こわ)れた。 The car's air conditioning broke. 今日(きょう)は暑(あつ)いからACを強(つよ)めにしよう。 It's hot today, so let's turn up the AC. ACをつけっぱなしで寝(ね)たら風邪(かぜ)を引(ひ)いた。 I caught a cold from sleeping with the AC on all night. 2. alternating current Electrical term for alternating current, as opposed to DC (direct current). ACで動(うご)く機械(きかい)です。 This is a machine that runs on AC power. このアダプターはAC100Vに対応(たいおう)している。 This adapter supports 100V AC. AC has two main meanings in Japanese:USAGE (Sense 1):In speech the usual word is エアコン; AC (or A/C) appears mostly on switches, remote controls and car control panels車(くるま)のAC: car air conditioningACを入(い)れる/つける: to turn on the ACACを切(き)る: to turn off the ACUSAGE (Sense 2):AC電源(でんげん): AC power supplyACアダプター: AC adapter対義語(たいぎご): DC (直流(ちょくりゅう)) general Added 2026.1.29 20:05 · Revised 2026.10.13 21:25 08500/08970_eeshii