Alert from a lab?

• Angry dog's growl
• [Stay back, human]
• Snarling dog's sound
• Sound of an angry dog
• Worrisome sound for a mail carrier
• [How exasperating!]
• [Return that bone at once, or I shall bare my teeth and yip!]
• [Stay out of my yard!]
• Boxer's threat

Wikipedia Word definitions in Wikipedia
GRR or grr may refer to: ANOVA gauge R&R , gauge repeatability and reproducibility, a statistical measure of the precision of a measurement system Gainesville Roller Rebels , a roller derby league based in Florida Great River Road , a series of roads which ...