Clade

Clade: Clade is a technical word that is simultaneously precise and approximate, a word with so many diverse applications that its meaning is impossible to discover from context. A clade includes all descendants (living, dead, contemporary, extinct, known, and unknown) of a common ancestor. Thus the clade of my grandfather includes all my cousins, and the clade of T-rex might include all birds. In theory any two living organisms belong to some common clade, while pardoxically they also belong to independent clades which exclude the other. Here is an example of a meaningless use of the term.

Cyanobacteria are in influential clade within the wider world of bacteria.

I expect any clade containing cyanobacteria includes all green plants, a circumstance that dwarfs the phrase the wider world of bacteria.