variants:
also B-chromosome
Medical Definition of B chromosome
: a small, usually heterochromatic chromosome present in addition to the normal complement of chromosomes in some members of a species
Note: B chromosomes do not contain any structural genes and have a highly variable pattern of inheritance separate from that of the normal chromosomal complement. They are most often found in plants and invertebrates.
Test Your Vocabulary
More Confusing Words—Quiz
-
- The magician
______
moved the selected card to the top of the deck.

Can you spell these 10 commonly misspelled words?
TAKE THE QUIZ
Spell words. Make bears.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridged
Words at Play
Ask the Editors
Share B chromosome