The Oxford Thesaurus An A-Z Dictionary of Synonyms - grain n.

1) seed, kernel, stone, pip, pit: Grains from each crop are stored ready for sowing. 2) cereal, corn, grist: The grain harvest was sparse this year. 3) particle, bit, fragment, crumb, speck, granule, morsel, mote, molecule, atom, fleck, iota, ounce, scrap, trace, scintilla, hint, suggestion, whit, jot (or tittle) , dab, soup‡on, taste, Colloq US and Canadian smidgen or smidgin: There's not a grain of truth in anything that's been said. 4) texture, pattern, fibre, weave, nap: Use a different kind of saw for cutting across the grain.