diff --git a/src/terms.jl b/src/terms.jl
index 6b9b376..8b040e1 100644
--- a/src/terms.jl
+++ b/src/terms.jl
@@ -170,7 +170,7 @@ import Base.<
 import Base.isless
 isless(t1::Term, t2::Term) = (t1 < t2)
 
-Base.hash(t::Term) = hash((t.L,t.S,t.parity))
+Base.hash(t::Term, h::UInt) = hash((t.L,t.S,t.parity), h)
 
 include("xu2006.jl")