Which dimension in Google Analytics indicates where users arrived from, such as "organic search" or "referral"?

The default channel grouping dimension in Google Analytics provides a comprehensive categorization of the various ways users arrive at a website. This grouping includes broad categories like "organic search," "referral," "direct," and others, which simplify the analysis of traffic sources.

Using the default channel grouping allows marketers and analysts to see which channels are driving the most traffic and conversions, making it easier to assess the effectiveness of different marketing efforts. This feature aggregates traffic into predefined buckets, enabling straightforward interpretation of user acquisition data.

While traffic source might seem similar at first glance, it typically presents information in a more granular manner, breaking down sources into detailed categories but not necessarily encompassing the broad channels directly like the default channel grouping does. User acquisition focuses specifically on how new users arrive and might involve dimensions such as source/medium but isn't about categorization in the same broad sense. Session medium falls under specific attributes of session data and does not encompass the wider view provided by the default channel grouping.