Termite nests are simply put nests built by termites to house their colony. The nests themselves however are not simply built, they tend to be very intricate and elaborate structures made using but not limited to a combination of saliva, faeces, mud, soil, chewed wood and cellulose. In general during the construction of the nest a termite will deposit fecal matter to cement particles in place.
There are different types of termites so of course there are different types of nests. The most common type of termite is the drywood termite (family Hodotermitidae) and these termites are the ones that are usually building a nest in your the roof or walls of your house or destroying your furniture. This type of nest is built by the termites by excavating into the wood. This type of nest is an irregular network of galleries in the wood with no external openings except the ones that are temporarily made during the initial swarming process. The reason for this is because the termites eat the wood that is becoming their nest so they do not need to go back out.
This type of nest contains partitions which are either lined and/or coated with plaster made of fecal matter or fecal matter itself from the termites. These partitions then make up the galleries which house and protect them.
Termites themselves are very fragile and weak insects and are easily overpowered by predators such as ants when exposed. So their nests must also function as protection as well as a living area which is why most nests are commonly built underground, inside fallen trees, in large pieces of timber and high on top of living trees. Some specific species also build nests above the ground and these usually turn into mounds.
A termite nest has many functions and serves different purposes usually simultaneously all year round. The termite nest also provides areas specifically for the termites to reproduce without having to worry about predators attacking them in this vulnerable state. Water is also collected for the termites by the nest itself through condensation, giving yet another reason the termites never have to leave the nest. The termite nest itself can be compared to a little city that is self sufficient bringing sustenance and protection to it’s inhabitants.