drug of abuse: a drug that is taken for nonmedicinal reasons (usually for mind-altering effects); drug abuse can lead to physical and mental damage and (with some substances) dependence and addiction
entity: that which is perceived or known or inferred to have its own distinct existence (living or nonliving)
rule of evidence: (law) a rule of law whereby any alleged matter of fact that is submitted for investigation at a judicial trial is established or disproved