Not a True Nut, This Fruit Is the Base of Marzipan
Puzzle 20 of Famous Horses Hard Pack
Question is: Not a True Nut, This Fruit Is the Base of Marzipan
and the answer is: ALMOND
Word Meaning:
ALMOND — (countable) The seed within the drupe of a small deciduous tree in family Rosaceae, Prunus amygdalus, considered a culinary nut.
Definitions from Wiktionary.