～本
～ほん · ～hon · JLPT N5 · noun
counter for long objects
✏️🍾 本 = root/trunk: a tree trunk is long, so 本 counts long thin things
本 is 木 (tree) with a mark at the base, meaning root or trunk. A trunk is the original long cylinder, so 本 counts pencils, bottles, umbrellas. Sound shifts: いっぽん (1), にほん (2), さんぼん (3).
本 — tree 木 + mark at base
本 is a pictograph of a tree (木) with a stroke at its base, marking the roots. From this 'root' meaning it extended to 'origin,' 'source,' and 'foundation.' In modern usage it also serves as a measure word for bound objects like books.