Wiktionary
bitplane
n. (context computing English) The set of bits stored at the same relative position in each byte and thus having comparable effects on the overall data, used for sound and image processing, etc.
Wikipedia
Bitplane
Bitplane is a provider of software for 3D and 4D image analysis for the life sciences. Founded in December 1992, Bitplane operates out of three offices in Belfast, United Kingdom, Zürich, Switzerland and South Windsor, Connecticut, United States.