容 is a compound of two ideas of space. On top sits 宀 mián, the roof radical, a shelter that defines an interior. Beneath it sits 谷 gǔ, a valley, the widest hollow the landscape offers. A roof set over a valley: a space large enough to take in whatever comes. That is the seed image of every sense the character will grow. To contain is the literal act; everything else extends it.

From the physical hollow, the meaning opens outward in three directions. First, capacity: a vessel, a hall, a hard drive all 容纳 (take in and hold). Second, the moral version of the same gesture: to make room for another person, to 容忍 (tolerate) and 宽容 (be lenient). To hold something is, after all, not to reject it. Third, and at first surprising, appearance: the 容貌 (face, looks) one presents, since the face is the surface that holds and shows a person. The same glyph that names the inside of a jar names the outside of a person.

One more sense rides along, almost an idiom in itself: the 容 of 容易 róngyì (easy). A thing is easy when there is ample room for it to happen, when nothing crowds it out. The valley under the roof has space to spare. In Japanese the character is read yō: 内容 naiyō (content, what is contained), 容易 yōi (easy), 美容 biyō (beauty care). The roof over the valley crossed the sea carrying its whole spread of meaning intact.

To hold a thing is, by definition, not to push it away. So the same character that names physical capacity names moral capacity: the room a person leaves for what they dislike. 容忍 is to endure it, 宽容 is to be generous about it, 容许 is to grant it leave to exist. The metaphor is consistent across the language: a tolerant person is said to have a large 度量 (literally, a large measure of holding), exactly as a large vessel has 容量.

The face is the surface that holds and shows a person, so 容 also means appearance, especially the human face: 容貌 (looks), 面容 (countenance), 笑容 (a smile). Beauty care is 美容, literally "to beautify the 容." And tucked into the most common word of all, 容易 (easy), the character carries a quieter sense: there is ample room, nothing crowds the task, so it goes smoothly.

Hold the picture: a roof set over a valley. The widest hollow in the land, given a shelter that says "everything here is held." That single image binds every meaning the character carries. A jar holds water, so 容量 is its capacity. A heart holds grievances without lashing out, so 宽容 is to be forgiving. A face holds a person's whole bearing, so 容貌 is one's looks and 笑容 is the smile worn upon it. And when a valley has room to spare, a thing slips through with no resistance, so 容易 means easy.

Two patterns repay learning. First, the negation 不容 (brooks no, leaves no room): 不容置疑 (beyond doubt), 义不容辞 (a duty one cannot decline). To refuse room is the strongest form of refusal. Second, the poise of 从容: the composed person is one with space inside, never crowded, never rushed. When you next reach for 容, ask what is being held, and the right sense will surface: a vessel, a person's patience, or a face.