diff --git a/font-src/meta/aesthetics.ptl b/font-src/meta/aesthetics.ptl
index 2c52a0b45..a09694525 100644
--- a/font-src/meta/aesthetics.ptl
+++ b/font-src/meta/aesthetics.ptl
@@ -16,7 +16,7 @@ export : define [calculateMetrics para] : begin
 	define Descender : fallback para.descender (XH - CAP)
 	define Contrast : fallback para.contrast 1
 	# Key metrics for symbols
-	define SymbolMid : fallback para.SymbolMid (XH * 0.65)
+	define SymbolMid : fallback para.symbolMid (XH * 0.65)
 	define ParenTop : SymbolMid + para.parenSize / 2
 	define ParenBot : SymbolMid - para.parenSize / 2
 
diff --git a/font-src/support/parameters.js b/font-src/support/parameters.js
index 5c634b56a..64cb9551f 100644
--- a/font-src/support/parameters.js
+++ b/font-src/support/parameters.js
@@ -126,7 +126,7 @@ const metricOverrideHandlers = {
 	leading: numericFieldHandler,
 	winMetricAscenderPad: numericFieldHandler,
 	winMetricDescenderPad: numericFieldHandler,
-	SymbolMid: numericFieldHandler,
+	symbolMid: numericFieldHandler,
 	parenSize: numericFieldHandler,
 	powerlineScaleY: numericFieldHandler,
 	powerlineScaleX: numericFieldHandler,
diff --git a/params/parameters.toml b/params/parameters.toml
index 96595e569..ef9227fea 100644
--- a/params/parameters.toml
+++ b/params/parameters.toml
@@ -17,7 +17,7 @@ xheight = 530      # X-height.
 winMetricAscenderPad  = 0 # Padding of Win ascnder metrics to avoid clipping. See #343
 winMetricDescenderPad = 0 # Padding of Win descender metrics to avoid clipping. See #343
 
-SymbolMid = 340    # Center of parens, maths, geometrics...
+symbolMid = 340    # Center of parens, maths, geometrics...
 parenSize = 966    # Size of parens, brackets, braces, slashes, etc.
 operSize = 0.80    # Size of mathematical operators (cups, etc.)
 tackSize = 0.80    # Size of logical operators (tacks, etc.)