nounAinmfhocal1militarymíleatadaingeanmasc1cmu2strongholdtheir home pitch has always been a real fortressbhí siad riamh deacair a shárú ar a bpáirc féinDerry has been a fortress for the partytá an páirtí thar a bheith láidir i nDoire3somewhere inaccessibledúnmasc1cmudaingeanmasc1cmuthe office is like a fortresstá an oifig mar a bheadh daingean ann