air-condition UK /ˈɛə kənˌdɪʃn̩/US /ˈɛɹ kənˌdɪʃ(ə)n/ verb1 •To mechanically cool a space or an entire structure.In hot, muggy climates, some people air-condition their garage. formsair-conditioned · air conned · air-conditioning · air conditions · air-conditions