half; 50%
5 parts; 5%
equality; equal footing; tie; (even) match
「五分」 has other readings with different meanings.
勝負は五分五分だと思う。
I think the odds are fifty-fifty.
五分の確率で雨が降るらしい。
There seems to be a fifty percent chance of rain.
両者の力は五分だった。
The strength of both sides was evenly matched.