KanjiJLPT N2
Include

contain, include, hold in the mouth, bear in mind, understand, cherish

Mnemonic

Right now, open your mouth and include every last grape in one massive bite! Your cheeks swell like a chipmunk's as you hold them all inside. To include is to keep something contained within your mouth — held now, savored later.
Additional thoughts
Picture a chipmunk stuffing its cheeks right now — everything included inside those puffy cheeks. The mouth is the container; now is the urgent moment of cramming it all in. Now + Mouth = holding within = Include.
Quick recall
Right now, stuff your mouth to include everything inside like a chipmunk.

Details

The keyword for 含 is include. This kanji conveys the idea of holding something within, containing, or keeping something inside—much like holding something in one's mouth. It extends beyond the physical sense to mean including or encompassing something as part of a larger whole. The nuance emphasizes the idea of something being held or harbored internally, whether it be a substance, a meaning, or an implication.
On'yomi
がん
Kun'yomi
ふく.む、ふく.める

Used in kanji