[fuller's earth] n [[1]fuller; fr. its earlier use as fulling agent] (15c): an earthy substance that consists chiefly of clay mineral but lacks plasticity and that is used as an adsorbent, a filter medium, and a carrier for catalysts
FULLER'S EARTH
Meaning of FULLER'S EARTH in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012