Noun:

1. mail consisting of large numbers of identical items (circulars or advertisements) sent to individual addresses at less than 1st-class rates and paid for in one lot

Bulkan布尔坎bulkn.体积；容积；大块；大部分；大批adj.散装的；大量的vt.使膨胀；使成堆vi.膨胀；显得重要bulk mineral materiel矿物散料bulk conductive glass体导电玻璃bulk viscosity of oil主体粘度bulk effect amplifier体效应放大器bulk-cargo handling散装货物的装卸bulk amorphous alloys大块非晶合金bulk coating holiadys大块涂层缺陷bulk ciphering device总体加密设备bulk liquid chemicals散装液体化学品bulk acoustic filters体声波滤波