For instance formal informal
There are many tourist attractions to visit in the city. For example, the botanical garden has numerous displays of plants from all over the world.
They intend to buy the tickets, via the Internet for instance.
Sleep deprivation, for instance, can cause stress.
There is usually commas before and after the phrase "for instance".
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In logic, "a fact, a case, an example" (a sense in English from early 15c.), from Medieval Latin instantia, which translated Greek enstasis. This led to for instance "as an example" (1650s), and the noun phrase "give (someone) a for instance" (1953, American English). The general sense "anything that illustrates a general type" was in use by 19c.