This is the 5893rd most frequent Japanese word.
まんなか
"まんなか" means "middle" or "center."
Here, 'まんなか' refers to the central part of the picture.
この絵のまんなかに大きな太陽があります。
In the center of this picture, there is a large sun.
In this case, 'まんなか' is being used to specify the middle location on the table.
テーブルのまんなかに花瓶を置いた。
I placed a vase in the middle of the table.
'まんなか' here indicates the position within the group.