Weapon of both - one's own and alien kinds- A type of Śastra (weapon or instrument of violence);
that animate or ananimate substance which, when used, kills a living being of both one's own kind and alien kind. E.g.- water mixed with soil acts as the weapon for other soil.
(ĀBhā 1.19)
See - Svakāyaśastra, Parakāyaśastra.