[um.bi.li.cus] n, pl um.bi.li.ci or um.bi.li.cus.es [L--more at navel] (ca. 1615) 1 a: navel 1 b: any of several morphological depressions; esp: hilum 1
2: a central point: core, heart
Merriam-Webster English vocab.Английский словарь Merriam Webster.2012