variety of evergreen tree, cedar
枏 refers to a type of evergreen tree, specifically a variety of cedar. Its meaning is narrow and botanical, without broader abstract extensions.
枏 combines 木 (tree) with 冄, which likely contributes the sound. The character is used for a specific evergreen tree, but the exact historical development of 冄 in this context is uncertain.
The tree radical 木 on the left marks this as a type of tree. The right side 冄 looks like a stylized evergreen with layered branches, helping you remember it is a cedar-like evergreen.
For ナン, picture a nun planting a cedar tree: nun -> ナン, and the tree 木 is the evergreen she tends.