单词microdot
n.: 缩微影印文件（约一毫米）；超小型药丸；（尤指）小粒迷幻药
网络: 微粒；网点；微粒照片
微点照片，缩微影印文件（约一毫米）:
a very small photograph about one millimetre in size, usually of a printed document
超小型药丸；（尤指）小粒迷幻药:
a very small round piece of a drug, especially the illegal drug LSD
【摄影】微点拷贝,微点照片〔进行间谍活动等拍摄文件等用〕
微缩点
复数：microdots
You want to leave the smallest imprint possible: a microdot.
你应该尽可能让留下的印迹越小越好：微微一点。
Each microdot is the size of a grain of sand and contains an identifier.
每颗微粒都是一粒沙粒的大小并且包含一个辨识码。
There exists an extended set of early Triassic intermediate-acid volcanics closely related to microdot gold ore in Southwestern Guangxi.
桂西南广泛发育一套与微粒型金矿密切相关的早三叠世中酸性火山岩。
The recipient would read the microdot with a special viewer.
情报接收者需要特殊的放映设备才能阅读胶片信息。
this planet Earth is a mere microdot in the universe.
地球这个行星，只是宇宙中一颗微尘而已。