Car Seats and Booster Seats

Car Seat Glossary



Adjustable foot: Part of detachable base that can be raised or lowered to allow a rear-facing car seat to be installed at the correct recline angle.

Aftermarket products: Parts and products sold for replacement or as accessories to original equipment – sometimes referred to as "non-regulated" products. Not recommended for use with car seats, unless made or allowed by original car seat manufacturer for use with its product. Check product instructions.

All-in-one seat: This type of seat can change from a rear-facing car seat to a forward-facing car seat and then to a booster seat as a child grows.

Automatic locking retractor: This is a type of retractor that provides the ability to "lock" the seat belt at a set position. This is an important piece when installing car seats. Check vehicle owner's manual for more information.


Belt path: This is the place on a car seat or booster seat where a seat belt or lower anchor attachment is placed to secure car seat in vehicle.

Belt-positioning booster seat: See booster seat.

Booster seat: A booster seat correctly positions the seat belt by "boosting" the child so the lap and shoulder belts fit properly. The lap belt should be low and snug across the hips, and the shoulder belt should fit across the chest and not rest against the neck or face. Proper belt fit is very important. Booster seats can have high backs (for use in vehicles with no head restraints) or can be no-back/backless seats (for use in vehicles with head restraints).

Buckle: Accepts the latch plate and holds the seat belt in place.


Car bed: A restraint, usually for small, premature, or medically fragile babies who should ride lying down either on their backs or on their stomachs. In most cases, the baby lies flat. The vehicle seat belt, is used to anchor the car bed perpendicular to the direction of travel. The infant's head is placed toward the center of the vehicle and not next to the door. An internal harness secures the child in the car bed. Be sure to carefully read the manufacturer’s instructions as there may be other methods of securing allowed for certain car beds.

Caregiver: A person responsible for a child's well-being and safety.

Carry handle: Plastic handle attached to infant car seats (rear-facing only) that can be used to carry car seat when removed from vehicle.

Car seat: A child restraint (CR), a child restraint system (CRS), or a child restraint device (CRD): A crash-tested seat, device or system that is specially designed to provide child crash protection. General terms for these systems include child safety seats, car seats, boosters or booster seats, vests or car beds, and those items which meet Federal Motor Vehicle Safety Standards (FMVSS) 213.

Chest clip: Plastic buckle or clasp that holds the harness shoulder straps together over the child’s chest and is positioned at child’s armpit level. Also called retainer clip.

Children with special transportation needs: Children whose physical or behavioral conditions sometimes make the use of specially designed restraint systems necessary.

Combination seat: A type of forward-facing car seat that is used with an internal harness system to secure a child. With removal of the internal harness, it can be used as a belt-positioning booster.

Convertible seat: A car seat that converts from rear-facing for babies and smaller children to forward-facing for older and larger children.


Detachable base: A separate base for a rear-facing only car seat that can be installed in the vehicle. The car seat portion can be removed from the base and used as a carrier.


Emergency locking retractor: A retractor on a seat belt system that locks when the vehicle slows or stops suddenly.


Forward-facing car seat: A car seat intended for use only in the forward-facing position for a child at least 1 year old and at least 20 pounds, up to the specified height and weight limits of the seat, set by the manufacturer.

Federal Motor Vehicle Safety Standards: Regulations that define minimum safety performance requirements for motor vehicles or items of motor vehicle equipment. These regulations are intended to protect the public from unreasonable risk of crashes that occur as a result of the design, construction, or performance of motor vehicles or related equipment. The regulations are also designed to protect the public against unreasonable risk of death or injury in the event crashes do occur. The standard that applies to car seats is FMVSS 213.


Harness: Straps that keep the child in the car seat and distribute crash forces. Infant (rear-facing only), forward-facing only, combination, convertible, and all-in-one car seats come equipped with harness straps which are fed through harness slots.

Harness buckle: Where the harness system connects and locks. This device secures the straps that contact the child's shoulders, hips, and groin.

Harness retainer clip: See chest clip.

Harness adjuster: Part used to tighten or loosen the harness straps of a car seat.

Harness slots: Places on car seat where the harness straps are fed through the seat shell.

High-back booster seat: See booster seat.


Infant car seat: See rear-facing-only seat.

Inspection station: A dedicated location staffed by Child Passenger Safety Technicians who are certified to teach parents and caregivers how to install their car seats. An inspection station may also be referred to as a "seat checking station."


Labels: Information required by Federal standards affixed to car seats or booster seats.

Lap belt: A seat belt that is secured to the framework of a seat or car and fastens across the lap of a driver or a passenger.

Latch plate: The seat belt part that connects the seat belt webbing to a buckle in the vehicle.

Level indicator: Part of car seat that helps identify correct rear-facing recline angles. Recline angle is important especially for young babies as it keeps their fragile necks and heads from falling forward and restricting their airways.

Locking clip: Holds a car seat in the proper position during normal driving when no other locking mechanism is available.

Lower anchors: Horizontal bars in the vehicle seat that provide a secure anchor for the car seat's lower attachments.

Lower anchor attachments: Attachments used in place of vehicle seat belt to secure car seat or booster seat. Consists of lower anchor connectors and the lower anchor strap for flexible lower anchor attachments.


Rear-facing car seat: Refers to the position where the child's car seat is turned to face the back of the vehicle. The rear-facing position supports the entire head, neck, and back, and cradles and moves with the child to reduce stress to the neck and spinal cord in a crash.

Rear-facing-only seat: A child restraint system designed for use only by a young child in a rear-facing position. Also called an infant car seat.

Recalls: Voluntary or required actions taken by manufacturers in conjunction with NHTSA to correct problems or deficiencies after products have been distributed or sold. Manufacturers must offer free repair or replacement for products recalled for violations of safety standards.

Recline adjustor: Adjusts the angle of the car seat so the child is in the proper position in either the rear-facing or forward-facing position (when child has outgrown the seat limits for rear-facing use).

Registration card: A postage-paid return card that comes with every car seat; should be returned to the manufacturer so owners can be notified of any recalls.

Retractor: A mechanism that works with the seat belts to gather and store extra seat belt webbing.


Safety belt: See seat belt.

Seat belt: The webbing, anchor, and buckle system that restrains a passenger or car seat in a vehicle; also known as a safety belt.

Seat Belt Syndrome: A range of symptoms that might occur as a result of the seat belt doing its job in a crash or sudden braking. Children should be buckled in with a lap and shoulder belt, to provide upper body protection. If a child uses a lap belt only, he or she can suffer internal organ injuries and injuries to the lumbar spine (lower back).

Shell: Molded plastic and/or metal structure of car seat or booster seat. Also called frame.

Smart Air Bag System: Also known as advanced air bags. A smart air bag system detects when a child is present and automatically deactivates the air bag or enables it to deploy safely. Manufacturers who do not provide a qualifying "smart" system would be required to have new and more prominent air bag warning labels inside the vehicle. Manufacturers would also be permitted to install cutoff switches so parents can deactivate the passenger air bag when a child is seated in front of it.

Snug harness: Harness straps that do not allow slack; the strap lies in a relatively straight line without sagging yet does not press into the child's shoulders creating an indentation. You should not be able to pinch the webbing vertically.

Switchable retractor: A retractor that can be switched from emergency locking retractor to an automatic locking retractor for use when installing car seats.


Technician: Term used to refer to a person who has successfully completed the standardized Child Passenger Safety Technician certification course. The certification courses use a NHTSA training curriculum, and Safe Kids Worldwide serves as the certifying body.

Tether: Comprised of a tether strap and tether hook that 'anchors' the top of the car seat to the tether anchor in the vehicle. Keeps restraint from tipping forward on impact and can provide extra protection. The tether is located on the top rear of convertible, combination, and all-in-one car seats used forward-facing. Most rear-facing-only infant car seats do not use this equipment for installation.

Tether anchor: Hardware used to connect the tether at a designated anchor point in the vehicle.


Webbing: The fabric part of the seat belt that crosses the body and holds a person or a car seat in place.