fas·tig·i·ate \-jēə̇t\adjective orfas·tig·i·at·ed\-ēˌād.ə̇d\ Etymology: probably from (assumed) New Latin fastigiatus, from Medieval Latin fastigiatus lofty, from Latin fastigium top, extremity + -atus -ate : narrowing toward the top: a.: having or consisting of more or less upright clustered branches < the lombardy poplar is fastigiate > < the fastigiate cortex of the thallus of certain lichens > b.zoology: united into a conical bundle • fas·tig·i·ate·ly\-ēə̇tlē\adverb