"short horizontal line placed over a vowel to indicate length," 1827, from Latinized form of Greek makron, neuter of makros "long" (from PIE root *mak- "long, thin").
macrocosm
macroeconomic
macroeconomics
macroinstruction
macromolecule
macron
macropaedia
macrophage
macrophotography
macroscopic
macrospore
