male and female contacts, tab and blade, receptacle contact, plug and header
Gender is one of the fastest ways to order the wrong terminal correctly. The part number is real, the family is right, the wire range is right, and it is the opposite gender to the one the housing takes.
The convention in a harness is functional, not arbitrary. The energised side of a circuit is normally given the socket, because a recessed socket is much harder to short against a chassis or a dropped tool than an exposed pin. That is why a live feed from a battery or a fuse box usually terminates in a socket, with the pin on the switched or downstream side. The same logic governs what happens when a connector is unmated in the field with the circuit still live.
Housings come as mating pairs, commonly described as plug and header, or receptacle and cap, and the housing dictates which gender of terminal it accepts. A TE MQS receptacle takes MQS socket contacts; the mating header takes pins, or presents them already moulded in as a board-mount or module-mount header. Within families such as Aptiv GT 150, Yazaki 090 or Sumitomo TS, pin and socket terminals share a family name and differ by part number, sometimes by nothing else visible on a purchase order.
The trap in shortage sourcing is that pins and sockets go short independently. Demand across a programme is not symmetric, so a family can be freely available in one gender and unobtainable in the other. An offer for "GT 150 terminals" answers nothing until the gender is stated, and a buyer working under time pressure will read the family name and stop reading.
Harness Code states gender explicitly on every terminal quoted and checks it against the housing the part has to serve, because a right-family, wrong-gender delivery is a shortage that has changed shape rather than ended.
Related terms
Terminal / contact
A terminal, or contact, is the metal part crimped to a wire and inserted into a connector housing to make the electrical connection. Terminals are specified by family, gender (pin or socket), wire cross-section range, and plating, typically tin or gold.
Connector housing
A connector housing is the moulded plastic body that holds and positions the terminals of an automotive connector. It is sold separately from the terminals and seals it accepts, so a working connection is always a matched set of housing, terminal and seal, not a single part number.
Keying and polarization
Keying, or polarization, is the mechanical feature that stops a connector being mated the wrong way round or into the wrong mating half. Coding variants and colour coding distinguish otherwise identical connectors so a harness cannot be assembled or serviced incorrectly.