noun🔗ShareA secure or fortified place; a stronghold, a fortress."The castle served as the king's fastness during the long siege. "militaryarchitecturebuildingChat with AIVocabulary GamePractice Reading
noun🔗ShareThe state of being fast."The fastness of the internet connection is crucial for online learning. "qualitybeingChat with AIVocabulary GamePractice Reading
noun🔗ShareThe ability of a dye to withstand fading."The fabric's fastness ensured the colorful school banners would stay vibrant for years. "colormaterialtechnicalindustryqualityChat with AIVocabulary GamePractice Reading
