diff --git a/src/context.rs b/src/context.rs
index 5bf76b1..c685589 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -40,7 +40,8 @@ impl Context {
 
 		if {
 			Function::from_string(s).is_some() ||
-			Constant::from_string(s).is_some()
+			Constant::from_string(s).is_some() ||
+			freeunit_from_string(s).is_some()
 		} { return false }
 
 		for c in s.to_lowercase().chars() {
diff --git a/src/quantity/mod.rs b/src/quantity/mod.rs
index 4c9dc90..6861ca6 100644
--- a/src/quantity/mod.rs
+++ b/src/quantity/mod.rs
@@ -23,6 +23,7 @@ mod unit;
 pub use crate::quantity::unit::Unit;
 pub use crate::quantity::unit::FreeUnit;
 pub use crate::quantity::unit::WholeUnit;
+pub use crate::quantity::unit::freeunit_from_string;
 
 mod quantity;
 pub use crate::quantity::quantity::Quantity;