bacteriumyoudaoicibaDictYouDict[bacterium 词源字典]
bacterium: [19] Bacterium was coined in the 1840s from Greek baktérion, a diminutive of báktron ‘stick’, on the basis that the originally discovered bacteria were rod-shaped. At first it was sometimes anglicized to bactery, but the Latin form has prevailed. Related, but a later introduction, is bacillus [19]: this is a diminutive of Latin baculum ‘stick’, and the term was again inspired by the microorganism’s shape. Latin baculum is also responsible, via Italian bacchio and its diminutive form bacchetta, for the long French loaf, the baguette.
=> bacillus, baguette, débacle, imbecile[bacterium etymology, bacterium origin, 英语词源]
germyoudaoicibaDictYouDict
germ: [17] As its close relatives germane and germinate [17] suggest, germ has more to do etymologically with ‘sprouting’ and ‘coming to life’ than with ‘disease’. It comes via Old French germe from Latin germen ‘sprout, offshoot’, which may go back ultimately to the Indo- European base *gen- ‘produce’ (source of English gene, generate, genitive, etc).

The meaning ‘sprout, from which new life develops’ persisted into English (and still occurs in such contexts as wheatgerm – and indeed in metaphorical expressions like ‘the germ of an idea’). Then at the beginning of the 19th century it began to be used to put into words the idea of a ‘seed’ from which a disease grew: ‘The vaccine virus must act in one or other of these two ways: either it must destroy the germe of the small-pox … or it must neutralize this germe’, Medical Journal 1803.

By the end of the century it was an accepted colloquialism for ‘harmful microorganism’.

=> germane, germinate
micro-organism (n.)youdaoicibaDictYouDict
also microorganism, 1855, from micro- + organism.
anaerobeyoudaoicibaDictYouDict
"A microorganism that is able to, or can only, live in the absence of oxygen", Late 19th century: from an-1 + aerobe.
aerotolerantyoudaoicibaDictYouDict
"Of an anaerobic microorganism: not killed by oxygen; able to grow slowly in the presence of oxygen", 1970s; earliest use found in Proceedings of the National Academy of Sciences of the United States of America. From aero- + tolerant.
archaeayoudaoicibaDictYouDict
"Microorganisms which are similar to bacteria in size and simplicity of structure but radically different in molecular organization. They are now believed to constitute an ancient group which is intermediate between the bacteria and eukaryotes", Modern Latin (plural), from Greek arkhaios 'primitive'.
astroplanktonyoudaoicibaDictYouDict
"Hypothetical living material such as microorganisms or spores present in space, postulated as able to initiate or spread life on reaching a suitable environment", 1950s; earliest use found in John Burdon Sanderson Haldane (1892–1964), geneticist.
aerobeyoudaoicibaDictYouDict
"A microorganism which grows in the presence of air or requires oxygen for growth", Late 19th century: coined in French from Greek aēr + bios 'life'.