An avocado was a foodstuff. Graham O'Brien claimed it was a fruit, whilst Ryan Sinclair thought it was a vegetable. (TV: The Tsuranga Conundrum) It was apparently a natural anti-depressant. (PROSE: Shroud of Sorrow)
By the 67th century, Gifftan culture confused fruits such as pears and avocados for a legendary Earth hero called Avocado Pear. Such meant that Yoss Inkl named his son Avocado in honour of the humans Ryan Sinclair and Graham O'Brien, who assisted him during his birth. (TV: The Tsuranga Conundrum)
The planet Venofax had avocado seas. (PROSE: Normality) The Eleventh Doctor brought the Shroud to Venofax in order to defeat them, where they were weakened by the anti-depressant properties of the avocado seas. (PROSE: Shroud of Sorrow)
Behind the scenes[]
In the real world, the avocado is considered a fruit, although it might more accurately be called a single-seeded berry.