diff --git a/config.c b/config.c
index 51615389..9306a6e7 100644
--- a/config.c
+++ b/config.c
@@ -410,7 +410,7 @@ str_to_color(const char *s, uint32_t *color, bool allow_alpha,
 }
 
 static bool
-str_to_pt_or_px(const char *s, union pt_or_px *res, struct config *conf,
+str_to_pt_or_px(const char *s, struct pt_or_px *res, struct config *conf,
                 const char *path, int lineno, const char *section, const char *key)
 {
     size_t len = s != NULL ? strlen(s) : 0;
diff --git a/config.h b/config.h
index 18b0e0c0..fffc44aa 100644
--- a/config.h
+++ b/config.h
@@ -55,7 +55,7 @@ struct config_mouse_binding {
 };
 
 /* If px != 0 then px is valid, otherwise pt is valid */
-union pt_or_px {
+struct pt_or_px {
     int16_t px;
     float pt;
 };
@@ -91,12 +91,12 @@ struct config {
     config_font_list_t fonts[4];
 
     /* Custom font metrics (-1 = use real font metrics) */
-    union pt_or_px line_height;
-    union pt_or_px letter_spacing;
+    struct pt_or_px line_height;
+    struct pt_or_px letter_spacing;
 
     /* Adjusted letter x/y offsets */
-    union pt_or_px horizontal_letter_offset;
-    union pt_or_px vertical_letter_offset;
+    struct pt_or_px horizontal_letter_offset;
+    struct pt_or_px vertical_letter_offset;
 
     struct {
         int lines;
diff --git a/terminal.c b/terminal.c
index a5537732..0ea04fc5 100644
--- a/terminal.c
+++ b/terminal.c
@@ -610,7 +610,7 @@ err_sem_destroy:
 
 static int
 pt_or_px_as_pixels(const struct terminal *term,
-                        const union pt_or_px *pt_or_px)
+                   const struct pt_or_px *pt_or_px)
 {
     return pt_or_px->px == 0
         ? pt_or_px->pt * term->font_dpi / 72