Meanings
Origin
From Initialism of Not resistant to oil particles with 99% filtration efficiency in NIOSH air filtration ratings.
Full word history & related roots →Cite this entry
APA
N99. (n.d.). In WatkinsX Dictionary. Retrieved November 3, 2026, from https://dictionary.watkinsx.com/word/N99
MLA
“N99.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/N99. Accessed November 3, 2026.
Chicago
WatkinsX Dictionary, s.v. “N99,” accessed November 3, 2026, https://dictionary.watkinsx.com/word/N99.
Source: N99 on Wiktionary, CC BY-SA 4.0.