This is the 7976th most frequent Japanese word.
大形
Large size; large-scale.
Here, 大形 describes the machinery, emphasizing its extensive dimensions.
大形の機械は搬送が困難です。
Large machinery is difficult to transport.
In this context, 大形 metaphorically expresses the ambitious and grand nature of the dreams.
彼は大形の夢を持っている。
He has grand dreams.
The word 大形 refers to the large physical size of the animal.