Part or all of this entry has been imported from the 1913 edition of Webster’s Dictionary, which is now free of copyright and hence in the public domain. The imported definitions may be significantly out of date, and any more recent senses may be completely missing.
Ad for advertisement is struggling hard for general recognition; some of its compounds, e. g., ad-writer, want-ad, display-ad, ad-card, ad-rate, column-ad and ad-man, are already accepted in technical terminology.
[The researchers] noticed many of their pieces of [plastic marine] debris sported surface pits around two microns across. […] Closer examination showed that some of these pits did, indeed, contain bacteria, and that in several cases these bacteria were dividing and thus, by the perverse arithmetic of biological terminology, multiplying.