Gram-variable

[gram-vair-ee-uh-buh l]
adjective (often lowercase)
  1. of or relating to bacteria that stain irregularly with Gram's stain, being neither Gram-positive nor Gram-negative.

Origin of Gram-variable

First recorded in 1955–60; see origin at Gram's method
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018