Terry stop
In the United States, a "Terry stop" is a brief detention of a person by police on reasonable suspicion of involvement in criminal activity but short of probable cause to arrest.
The name derives from Terry v. Ohio, 392 U.S. 1 (1968), in which the Supreme Court of the United States held that police may briefly detain a person who they reasonably suspect is involved in criminal activity; the Court also held that police may do a limited search of the suspect's outer garments for weapons if they have a reasonable and articulable suspicion that the person detained may be "armed and dangerous".
To have reasonable suspicion that would justify a stop, police must be able to point to "specific and articulable facts" that would indicate to a reasonable police officer that a crime has been, is being, or is about to be committed. Reasonable suspicion depends on the "totality of the circumstances", and can result from a combination of facts, each of which is by itself innocuous.
The search of the suspect's outer garments, also known as a patdown, must be limited to what is necessary to discover weapons; however, pursuant to the "plain view" doctrine, police may seize contraband discovered in the course of a frisk, but only if the contraband's identity is immediately apparent.
