diff --git a/src/deca/ThDEC.jl b/src/deca/ThDEC.jl
index 00813ff..57aab47 100644
--- a/src/deca/ThDEC.jl
+++ b/src/deca/ThDEC.jl
@@ -24,8 +24,12 @@ export DECQuantity
 # this ensures symtype doesn't recurse endlessly
 SymbolicUtils.symtype(::Type{S}) where S<:DECQuantity = S
 
-struct Scalar <: DECQuantity end
-export Scalar
+abstract type AbstractScalar <: DECQuantity end
+
+struct Scalar <: AbstractScalar end
+struct Parameter <: AbstractScalar end
+struct ConstScalar <: AbstractScalar end
+export Scalar, Parameter, ConstScalar
 
 struct FormParams
     dim::Int
@@ -107,7 +111,7 @@ end
 export PatFormDim
 
 @active PatScalar(T) begin
-    if T <: Scalar
+    if T <: AbstractScalar
         Some(T)
     end
 end
@@ -225,7 +229,9 @@ abstract type SortError <: Exception end
 
 # struct WedgeDimError <: SortError end
 
-Base.nameof(s::Scalar) = :Constant
+Base.nameof(s::ConstScalar) = :ConstScalar
+Base.nameof(s::Parameter) = :Parameter
+Base.nameof(s::Scalar) = :Scalar
 
 function Base.nameof(f::Form; with_dim_parameter=false)
     dual = isdual(f) ? "Dual" : ""
@@ -269,7 +275,9 @@ end
 
 function SymbolicUtils.symtype(::Type{<:Quantity}, qty::Symbol, space::Symbol)
     @match qty begin
-        :Scalar || :Constant => Scalar
+        :Scalar => Scalar
+        :ConstScalar => ConstScalar
+        :Parameter => Parameter
         :Form0 => PrimalForm{0, space, 1}
         :Form1 => PrimalForm{1, space, 1}
         :Form2 => PrimalForm{2, space, 1}
diff --git a/test/decasymbolic.jl b/test/decasymbolic.jl
index bd82387..3a0cb92 100644
--- a/test/decasymbolic.jl
+++ b/test/decasymbolic.jl
@@ -7,6 +7,7 @@ using SymbolicUtils: symtype, promote_symtype, Symbolic
 using MLStyle
 
 # load up some variable variables and expressions
+c, t = @syms c::ConstScalar t::Parameter
 a, b = @syms a::Scalar b::Scalar
 u, v = @syms u::PrimalForm{0, :X, 2} du::PrimalForm{1, :X, 2}
 ω, η = @syms ω::PrimalForm{1, :X, 2} η::DualForm{2, :X, 2}
@@ -14,7 +15,9 @@ u, v = @syms u::PrimalForm{0, :X, 2} du::PrimalForm{1, :X, 2}
 # TODO would be nice to pass the space globally to avoid duplication
 
 @testset "Term Construction" begin
- 
+
+    @test symtype(c) == ConstScalar
+    @test symtype(t) == Parameter
     @test symtype(a) == Scalar
     @test symtype(u) == PrimalForm{0, :X, 2}
     @test symtype(ω) == PrimalForm{1, :X, 2}
@@ -22,6 +25,10 @@ u, v = @syms u::PrimalForm{0, :X, 2} du::PrimalForm{1, :X, 2}
     @test symtype(ϕ) == PrimalVF{:X, 2}
     @test symtype(ψ) == DualVF{:X, 2}
 
+    @test symtype(c + t) == Scalar
+    @test symtype(t + t) == Scalar
+    @test symtype(c + c) == Scalar
+
     @test symtype(u ∧ ω) == PrimalForm{1, :X, 2}
     @test symtype(ω ∧ ω) == PrimalForm{2, :X, 2}
     # @test_throws ThDEC.SortError ThDEC.♯(u)
@@ -30,6 +37,8 @@ u, v = @syms u::PrimalForm{0, :X, 2} du::PrimalForm{1, :X, 2}
     # test unary operator conversion to decaexpr
     @test Term(1) == Lit(Symbol("1"))
     @test Term(a) == Var(:a)
+    @test Term(c) == Var(:c)
+    @test Term(t) == Var(:t)
     @test Term(∂ₜ(u)) == Tan(Var(:u))
     @test Term(★(ω)) == App1(:★₁, Var(:ω))