The inner hole is about the size of a ten or so into the house. What does "in" mean?

The word "in" in "ten or so" is a quantifier that refers to the level of an old-fashioned house.

"In" as a quantifier to describe a house is not unusual. Especially in the description of some famous ancient houses commonly used. Ancient high officials, they built the house is also mostly "into the courtyard type". They are rich and powerful in addition to the pursuit of housing the internal components of the exquisite outside, the momentum should also be superior. Their houses in the "into" and "into" between, useful "patio" connection, but also in each room before leaving an open yard.

The courtyard houses are not ordinary people's homes, "into" and "into" the ladder-like vertical arrangement, their houses also extend to the left and right at the same time. This kind of courtyard house has hundreds of big rooms, can live a family of hundreds of thousands of people.

Extended information:

Jin is a Chinese character pronounced jin, which originally meant to point forward or upward. Move, develop, offer, present. Specific meanings include:

1. To move forward or upward, to develop, as opposed to to "to retreat": to go forward, to go up, to push, to leap, to retreat, to take, to strike, to stay, to walk (xíng ), to be.

2. As opposed to "out". To enter, to go inside: ~ factory, ~ school. Income or purchase: ~ payment, ~ item, ~ goods.

3. To eat, drink: ~ food. ~ meal. A drop of water has not been ~.

4. to offer, to present: ~ speech, ~ offering, ~ offering.

5, quantifier, old-fashioned house and yard levels: this mansion is two ~ yards.

6, promotion, e.g.: into pew (into use, to promote to an official position); into post (into an official position); into service (into an official rank).

References:

Baidu Encyclopedia_Jin