This is the 7194th most frequent Japanese word.
一部分
"One part" or "a portion."
The word '一部分' is used to signify a portion or segment of a larger entity, in this case, part of a plan.
計画の一部分が変更された。
Part of the plan has been changed.
Here, '一部分' specifies a damaged segment within the machine, implying it is not the whole machine that is broken.
その機械は一部分が壊れている。
That machine has a part that is broken.
In this context, '一部分' denotes an incomplete portion of the entire book, highlighting that it was not fully read.