alappillér angolul

cornerstone [cornerstones]▼◼◼◼noun
[UK: ˈkɔː.nə.stəʊn] [US: ˈkɔːr.nərˌstoʊn]

keystone [keystones]▼◼◼◻noun
[UK: ˈkiː.stəʊn] [US: ˈkiːˌstoʊn]