What's the "een" in Halloween?
late 13c., from Old French cople "married couple, lovers" (12c., Modern French couple), from Latin copula "tie, connection," from PIE *ko-ap-, from *ko(m)- "together" + *ap- "to take, reach." Meaning broadened mid-14c. to "any two things."
c.1200, from Old French copler, from cople (see couple (n.)). Related: Coupled; coupling.
coupling cou·pling n.
The act of uniting sexually.
See bigeminal rhythm.
The configuration of two different mutant genes on the same chromosome, leading to the likelihood they will both either be inherited or omitted in the next generation.
The degree to which components depend on one another. There are two types of coupling, "tight" and "loose". Loose coupling is desirable for good software engineering but tight coupling may be necessary for maximum performance. Coupling is increased when the data exchanged between components becomes larger or more complex.