Position
Average organic rank on the keywords where the product is on page 1.
The average organic rank over all captures in which the product was on page 1 for a keyword in your search. All variants of a product count together. Captures where it wasn't on page 1 are left out of the average; they show up in Coverage instead. Read the two together: Position tells you how high the product ranks, Coverage how broadly. The position trend compares each keyword's first and last capture in the period, and only keywords where the product was on page 1 at both.
Lower is better — position 1 is the top of the results.