Meanings
nounifdef (plural ifdefs)
plural ifdefs
- computingA construct in source code that allows another part of the code to run only if a specified identifier is defined in the program.
Origin
A keyword in various programming languages, short for if defined.
Full word history & related roots →Cite this entry
APA
ifdef. (n.d.). In WatkinsX Dictionary. Retrieved November 2, 2026, from https://dictionary.watkinsx.com/word/ifdef
MLA
“ifdef.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/ifdef. Accessed November 2, 2026.
Chicago
WatkinsX Dictionary, s.v. “ifdef,” accessed November 2, 2026, https://dictionary.watkinsx.com/word/ifdef.
Source: ifdef on Wiktionary, CC BY-SA 4.0.