petitionable,a.|pɪˈtɪʃənəb(ə)l| [f. petition n. + -able.] That allows, justifies, or involves, the making of a petition. 1898Westm.Gaz. 14 Mar. 2/1 A few suggestions for amending the Bankruptcy Act... 1. Reduce the petitionable amount from fifty pounds to five.