The Collaborative International Dictionary of English v.0.48:
Fuller \Full"er\, n. [AS. fullere, fr. L. fullo. See Full, v.
One whose occupation is to full cloth.
Fuller's earth, a variety of clay, used in scouring and
cleansing cloth, to imbibe grease.
Fuller's herb (Bot.), the soapwort (Saponaria
officinalis), formerly used to remove stains from cloth.
Fuller's thistle or Fuller's weed (Bot.), the teasel
(Dipsacus fullonum) whose burs are used by fullers in
dressing cloth. See Teasel.