What's the "een" in Halloween?
early 14c., "to check, verify, regulate," from Anglo-French contreroller "exert authority," from Medieval Latin contrarotulus "a counter, register," from Latin contra- "against" (see contra) + rotulus, diminutive of rota "wheel" (see roll (n.)). From a medieval method of checking accounts by a duplicate register. Sense of "dominate, direct" is mid-15c. Related: Controlled; controlling.
Control group in scientific experiments is attested from 1952 (from a sense of control attested since 1875).
1580s, from control (v.). Control freak is late 1960s slang.
control con·trol (kən-trōl')
v. con·trolled, con·trol·ling, con·trols
To verify or regulate a scientific experiment by conducting a parallel experiment or by comparing with another standard.
To hold in restraint; check.
A standard of comparison for checking or verifying the results of an experiment.
An individual or group used as a standard of comparison in a control experiment.
A standard of comparison for checking or verifying the results of an experiment. In an experiment to test the effectiveness of a new drug, for example, one group of subjects (the control group) receives an inactive substance or placebo , while a comparison group receives the drug being tested.