Intercourse means sex, or dealings between people. Sexual intercourse, social intercourse, commercial intercourse.
The general sense came first and is now nearly dead, because the sexual one has swallowed it — a nineteenth-century writer could describe daily intercourse with a neighbour and mean conversation. The Latin means a running between.
1nounsexualSexual activity between people.
“Doctors advise waiting a few weeks after giving birth before having intercourse again.”
2nounintercourseDealings between people.
“The two families had little social intercourse, though they lived on the same street.”
intercourse is a dealing.
Latin intercursus means a running between, from inter plus currere, to run. The general sense of dealings came first.
Proto-Indo-European
*ḱers-
Latin
intercursus
Old French
entrecours
English, today
intercourse
From Old French entrecours, from Latin intercursus.
Etymology from Wiktionary, CC BY-SA