I'm surprised it's in that many "synsets" in the Japanese Wordnet.

See below.

I do not know whether this is of any interest, but by mistake I searched for "ぶぶん" in the Combined Jpn-Eng. Naturally I would expect to see the entries in the special dicationaries come up, but I did not expect to see so many other entries, including a repeat of the main entry above. The list was as follows:-

部分 【ぶぶん】 (n) division; partition; partitioning; segmentation; sectionalization; sectionalisation; JWN-00397953-n
部分 【ぶぶん】 (n) fraction; JWN-03390207-n
部分 【ぶぶん】 (n) man; piece; JWN-03716327-n
部分 【ぶぶん】 (n) meronym; part name; JWN-06293746-n
部分 【ぶぶん】 (n) part; (n) portion; (n) region; (n) moiety; (n) piece; (n) division; (aj) partial; LS
部分 【ぶぶん】 (n) part; piece; JWN-09385911-n
部分 【ぶぶん】 (n) part; portion; JWN-03892891-n
部分 【ぶぶん】 (n) part; portion; component part; component; constituent; JWN-13809207-n 
部分 【ぶぶん】 (n) part; section; division; JWN-05867413-n
部分 【ぶぶん】 (n) partial; LG
部分 【ぶぶん】 (n) piece; JWN-03932203-n
部分 【ぶぶん】 (n) portion; section; part; (P)
部分 【ぶぶん】 (n) section; segment; JWN-04164989-n
部分 【ぶぶん】 (n) way; JWN-13285973-n
部分 【ぶぶん】 a part; BU

Apologies if this is a time-waster.