在(信件等)上做记号，加印记(以示邮资已付或免费邮寄)(stamp a mark on a letter，parcel， etc to show that postage has been paid;delivered free of postage) [T+n]：～letters/parcels给信/包裹上加盖邮戳;～ed envelopes加盖了邮戳的信封;～ing-machine自动邮戳盖印机