Kissing gate with yellow footpath markings
A kissing gate is a type of gate which allows people to pass through, but not livestock.
The normal construction is a half-round, rectangular, trapezoidal or V-shaped enclosure with a hinged gate trapped between its arms. When the gate is parked at either side of the enclosure, there is no gap to pass through. However, the gate can be pushed to give access to the small enclosure, then moved in the opposite direction to close the first opening and allow exit from the enclosure to the other side. The enclosure may be made large enough to accommodate pushchairs and wheelchairs. The gate itself is usually self-closing, to the side away from the land where animals are kept. The self-closing may be by hinge geometry but sometimes by a spring or weight.
This design of gate does not usually allow bicycles to be taken through, and they must be lifted over the fence. Alternatively they (or horses) may pass instead through an adjacent conventional gate, or an additional latch may allow the kissing gate itself to open fully for this purpose.
The etymology of the name is that the gate merely "kisses" (touches) the enclosure either side, rather than needing to be securely latched.
Disabled access 
The UK's Disability Discrimination Act states public services should make "reasonable adjustments" to allow disabled access. The Department for Environment, Food and Rural Affairs (DEFRA) in England has suggested in this context that kissing gates and stiles should be in time replaced or supplemented by a type that would allow access to a wider range of users. These concerns have partly now been addressed. The Equality Act 2010 has superseded the Disability Discrimination Acts and Defra, in October 2010, published a guidance document "Authorising Structures on Rights of Way. Good practice guidance for local authorities on compliance with the Equality Act 2010" Defra Equality Act path structure guidance. The Pittecroft Trust, a small UK charity, has published a summary of the Defra guidance Understanding the Defra guidance. Whilst neither of these documents lay down standards for kissing gate, they do require rigorous specification of these gates. The British Standard BS5709:2006 mentioned above fulfils that requirement. The overriding requirement is for any path structure, gate or kissing gate to cause the least restriction for users, whilst still providing the necessary level of animal constraint for farm animals.
See also 
Further reading 
Kissing gates are included in a British Standard: BS5709:2006: Gaps, Gates & Stiles ISBN 0-580-48107-7. The standard is functional rather than prescriptive.