Habituation is a word that refers to a decrease in an individual's response to stimuli after the stimuli are repeated. In other words, a sensation is ignored after a while.
Following you will find some examples of habituation.
A turtle draws its head back into its shell when its shell is touched. After being touched repeatedly, the turtle realizes it's not in danger and no longer hides.
When a couple moves into a new house by some train tracks, they find that the sound of the trains keeps them awake at night. After a while, they become desensitized to the noise and are able to ignore it.
Prairie dogs retreat into their holes at the sound of approaching human footsteps. When this occurs many times and the prairie dogs know the footsteps are not a threat, they no longer retreat at the sound of footsteps.
When you put on a pair of shorts for the first time over the summer, the sensation of air on your legs feels different. Once you've worn them for a while, however, you become used to the sensation and stop noticing it.
An abused cat is very wary of human touch, but once it realizes that its new owners pose no threat, it becomes used to petting.
A caged hamster becomes frightened when a person taps on its cage; however, when it realizes that the taps pose it no danger, it becomes used to hearing them.
Certain noises in a house cause a newborn baby to cry, until he or she becomes desensitized to the noises and they no longer frighten the child.
An individual purchases a new clock, but initially finds it difficult to concentrate while working in the room because of the clock's ticking. A few days pass, and the person is able to "tune out" the clock due to habituation.
Ducks in a small pond at a park are scared of people and fly away when approached. They become used to humans over time as they interact with them, and as people feed them, causing them to realize that the humans are not a threat.
The smell of a chocolate factory initially bothers a person who gets a job near one. One year later, the individual doesn't even notice the smell unless she thinks about it.
A newly-purchased pet cockatiel is initially scared of its owner's hand, and backs away or bites when its owner attempts to take it out of its cage. After a few days, the bird becomes used to the owner and readily hops onto his hand, realizing the owner does not pose a threat.
A snail is moving across a table. While initially tapping the table causes the snail to retreat into its shell, it eventually knows that the tapping is not a threat and continues its journey without retreating.
The creaking of an old hotel initially irritates a businessman and keeps him from sleeping; however, due to habituation, each night it bothers him less and less until finally he does not notice the creaking sound at all.
Now you have seen plenty of examples of habituation and you can recognize habituation in the world around you.