The fastest way to answer this question is to Google it. So let's do that.
Our first result comes from Oxford Languages, which gives a simple, computational definition for algorithms. Under this definition, algorithms are often described as recipes or instructions: they tell the computer what to do with inputs, such as numbers to be divided or costs to be summed.
As we've seen, much of the internet is driven by algorithms, which, while a computational concept, have taken on a larger cultural meaning. We speak of algorithms as the agents determining our newsfeeds, social media timelines, and advertisements. Algorithms seem tend to be discussed as if they have a mind of their own, when in reality they are meticulously programmed and manipulated by their creators. Journalistic and anthropological work has been done to investigate the producers of algorithms, but algorithmic ethnography is more interested in how users experience the virtual environments created by algorithms. Algorithmic ethnography is the study of immersive, algorithmically-driven online experiences.