-omics: this bugger is tough to adequately describe. In short, it represents all the fields of study in biology that concern themselves with every molecule of a certain type. For instance, the field of “genomics” will look at the entire genome and not at individual genes. The field of “proteomics” will study every protein in, for example, the human body. “Transcriptomics” concerns itself with every RNA molecule.
A useful definition of its areas of study is “all constituents considered collectively”. As such, genomics studies “genomes”; proteomics, “proteomes”; and transcriptomics, “transcriptomes”.
The etymology here is a bit more complex than usual, as the suffix is as new as the fields it qualifies. In Greek, the true suffix is not “-oma” but “-ma”. It seems that the “-o-” tagged along from a word like “mitome” which thus gave us “genome” and not “geneme”. From “genome”, we got “proteome”, “metabolome”, and the whole rest of them. So how did the “-ics” squeeze itself in to describe the field? Through beer. Read the whole (and short) story here.