Botany

What is the botanical term—often used as a synonym of “stone fruit”—for a one-seeded fruit with a hardened innermost layer (endocarp or “pit,” “stone,” etc.), a fleshy middle layer (mesocarp), and thin skin (exocarp)? Examples include peaches, plums, cherries, mangoes, olives, and almonds.

Flowering plants (angiosperms) are divided into two classes based on the number of seed leaves present. Those with one seed leaf have a name with the prefix “mono-“, whereas those with two begin with “di-“. What four-syllable word completes the names of these two classes?