SPARKLINE is a function in Google Sheets that allows you to create a small, simple chart, also known as a sparkline, within a single cell. The function takes a range of data as its input and generates a visual representation of that data in the form of a line or bar chart.

The syntax for the SPARKLINE function is as follows:

SPARKLINE(data, [options])

The "data" argument specifies the range of cells containing the data you want to visualize, and the "options" argument is optional and can be used to customize the appearance of the sparkline chart.

Some of the options that can be used with the SPARKLINE function include specifying the type of chart (line or bar), the color of the chart, the minimum and maximum values to be displayed on the chart, and whether to display markers for each data point.