Entry 1 sense Webster, 1913 Isolation /(ī`sō̇*lā"shŭn)/ · I·so·la·tion · IPA /ˌaɪsəˈleɪʃən/ 01 n. The act of isolating, or the state of being isolated; insulation; separation; loneliness. 1. The act of isolating, or the state of being isolated; insulation; separation; loneliness.