The female part of a seatbelt is called the seat belt buckle.
It is the slot where the metal tongue (male part) is inserted and locked.
The buckle contains the release button used to disengage the belt.

The “female part” of a seat belt is most commonly called the:

Seat Belt Buckle (Receiver / Latch)

Also known as:
- Buckle
- Latch
- Receiver buckle
- Seat belt receptacle

This is the part mounted near the seat where you insert the metal tongue (the “male” part).

Main Components

1. Buckle Housing

The outer casing (usually plastic + metal inside)
Protects the internal locking mechanism

2. Latch Mechanism (Locking System)

The core internal part
Uses a spring-loaded metal catch that locks onto the tongue
Designed to:
- Lock instantly when inserted
- Withstand high crash forces

3. Release Button

The red button you press to release the belt
Connected to the internal latch
Must meet safety standards for:
- Easy release in emergencies
- Not releasing accidentally

4. Pretensioner (in modern cars)

Advanced versions include a pretensioner system
Tightens the belt automatically during a crash
Works with the airbag system

5. Seat Belt Warning Sensor

Detects whether the belt is latched
Sends signal to:
- Dashboard warning light
- Seat belt alarm

How it works ?

You insert the metal tongue into the buckle
Internal latch clicks and locks it in place
During a crash:
- Locking mechanism holds firmly
- Pretensioner (if present) tightens the belt
Press button → latch releases → belt comes out