1 Used other than as an idiom: see outer ,â core. ( 2 planetology) The hot liquid material found near the centre of some planets, distinct from the solid inner core. ( 3 geology) The part of the Earth between the mantle and inner core, responsible for generating the planet's magnetic field. 4  Link/Cite.
Differential Staining is a staining process which uses more than one chemical stain. Using multiple stains can better differentiate between different microorganisms or structures/cellular components of a single organism.
A counterstain is a stain with colour contrasting to the principal stain, making the stained structure easily visible using a microscope. Examples include the malachite green counterstain to the fuchsine stain in the Gimenez staining technique and the eosin counterstain to haematoxylin in the H&E stain. In Gram staining, crystal violet stains only Gram-positive bacteria, and safranin counterstain is applied which stains all cells, allowing the identification of Gram-negative bacteria as well. An alternative method uses dilute carbofluozide.