Meaning of 川細小 in Japanese

It seems that your search contains the following:

Definition of 川細小

かわ(kawa) · がわ(gawa) 【川 ·河】

(n) river; stream
この川はあの川の３倍長い。
This river is three times longer than that one.
(suf) the .... river; (suffix used with the names of rivers)
信濃川と阿賀野川ではどちらが長いですか。
Which is longer, the Shinano River or the Agano River?

さいしょう(saishou) 【細小】

いさら(isara) · いささ(isasa) 【細小 ·些 ·細】