An example of a technical term in a scientific field that could be perceived by a novice or non-specialist as a figure of speech. Erythroblastic 'islands' may seem to be a metaphor, but this term has a precise meaning:
"Erythroblastic islands are specialized microenvironmental compartments within which definitive mammalian erythroblasts proliferate and differentiate. These islands consist of a central macrophage that extends cytoplasmic protrusions to a ring of surrounding erythroblasts. The interaction of cells within the erythroblastic island is essential for both early and late stages of erythroid maturation. It has been proposed that early in erythroid maturation the macrophages provide nutrients, proliferative and survival signals to the erythroblasts, and phagocytose extruded erythroblast nuclei at the conclusion of erythroid maturation."
Manwani D. & Bieker J. J. (2008) The erythroblastic island. Current Topics in Developmental Biology, 82: 23-53. doi: 10.1016/S0070-2153(07)00002-6.
