一粒[hitotsubu] (a) grain
一粒子既約[ichiryuushikiyaku] one particle irreducible (physics)
一粒種[hitotsubudane] an only child
雨粒[amatsubu] raindrop
穀粒[kokuryuu] kernel

素粒子[soryuushi] elementary particle
素粒子加速器[soryuushikasokuki] particle accelerator
大粒[ootsubu] large grain
長粒米[chouryuumai] long grain rice
麦粒腫[bakuryuushu] sty (on the eyelid)

一宿一飯[isshukuippan] (being beholden to someone for a favor of) a night's lodging and a meal
一膳飯屋[ichizenmeshiya] quick lunch
一飯[ippan] bowl of rice
五目飯[gomokumeshi] dish of rice, fish and vegetables
御飯[omanma] cooked rice

桜飯[sakurameshi] rice boiled with soy sauce and sake
残飯[zanpan] food scraps
鮨飯[sushimeshi] rice seasoned with vinegar, sugar and salt, used for preparing sushi
炊飯器[suihanki] rice cooker
赤飯[sekihan] red rice (beans and mochi) for auspicious occasions