Related topics: Defence
en·trench·ment /ɪnˈtrentʃmənt/ noun 1. [uncountableU]CHANGE YOUR MIND when an attitude, belief etc becomes firmly established 〔态度、信念等的〕牢固确立
2. [countableC]PMD a system of trenches (=long deep holes) dug by soldiers for defence or protection 堑壕,战壕