From Greek 'makros' (long, large) — the systematic opposite of 'micro-' in scientific vocabulary.
A prefix meaning 'large,' 'long,' or 'on a large scale,' derived from Greek and used to form words indicating largeness, breadth of scope, or large-scale analysis.
From Greek 'makrós' (μακρός, long, large, tall, far, deep), from PIE *meh₂k- (long, thin). In Greek, 'makrós' contrasted systematically with 'mikrós' (small), and this opposition has been imported into English scientific and philosophical vocabulary. The PIE root also produced Latin 'macer' (thin, meager), which evolved
The diacritical mark called a 'macron' — the horizontal line placed over a vowel (ā, ē, ī) to indicate a long sound — is literally named 'the long one' from Greek 'makrón' (μακρόν), the neuter form of 'makrós.' Every time a linguistics student writes a macron over a vowel, they are using the same Greek word that forms the 'macro' in 'macroeconomics.'