diff --git a/src/uu/seq/src/numberparse.rs b/src/uu/seq/src/numberparse.rs
index b22cf90c0..469917255 100644
--- a/src/uu/seq/src/numberparse.rs
+++ b/src/uu/seq/src/numberparse.rs
@@ -73,30 +73,13 @@ fn parse_no_decimal_no_exponent(s: &str) -> Result<PreciseNumber, ParseNumberErr
         }
         Err(_) => {
             // Possibly "NaN" or "inf".
-            //
-            // TODO In Rust v1.53.0, this change
-            // https://github.com/rust-lang/rust/pull/78618 improves the
-            // parsing of floats to include being able to parse "NaN"
-            // and "inf". So when the minimum version of this crate is
-            // increased to 1.53.0, we should just use the built-in
-            // `f32` parsing instead.
-            if s.eq_ignore_ascii_case("inf") {
-                Ok(PreciseNumber::new(
-                    Number::Float(ExtendedBigDecimal::Infinity),
-                    0,
-                    0,
-                ))
-            } else if s.eq_ignore_ascii_case("-inf") {
-                Ok(PreciseNumber::new(
-                    Number::Float(ExtendedBigDecimal::MinusInfinity),
-                    0,
-                    0,
-                ))
-            } else if s.eq_ignore_ascii_case("nan") || s.eq_ignore_ascii_case("-nan") {
-                Err(ParseNumberError::Nan)
-            } else {
-                Err(ParseNumberError::Float)
-            }
+            let float_val = match s.to_ascii_lowercase().as_str() {
+                "inf" | "infinity" => ExtendedBigDecimal::Infinity,
+                "-inf" | "-infinity" => ExtendedBigDecimal::MinusInfinity,
+                "nan" | "-nan" => return Err(ParseNumberError::Nan),
+                _ => return Err(ParseNumberError::Float),
+            };
+            Ok(PreciseNumber::new(Number::Float(float_val), 0, 0))
         }
     }
 }
@@ -483,11 +466,23 @@ mod tests {
     #[test]
     fn test_parse_inf() {
         assert_eq!(parse("inf"), Number::Float(ExtendedBigDecimal::Infinity));
+        assert_eq!(
+            parse("infinity"),
+            Number::Float(ExtendedBigDecimal::Infinity)
+        );
         assert_eq!(parse("+inf"), Number::Float(ExtendedBigDecimal::Infinity));
+        assert_eq!(
+            parse("+infinity"),
+            Number::Float(ExtendedBigDecimal::Infinity)
+        );
         assert_eq!(
             parse("-inf"),
             Number::Float(ExtendedBigDecimal::MinusInfinity)
         );
+        assert_eq!(
+            parse("-infinity"),
+            Number::Float(ExtendedBigDecimal::MinusInfinity)
+        );
     }
 
     #[test]
diff --git a/tests/by-util/test_seq.rs b/tests/by-util/test_seq.rs
index 8f879263b..da28181eb 100644
--- a/tests/by-util/test_seq.rs
+++ b/tests/by-util/test_seq.rs
@@ -623,11 +623,21 @@ fn test_neg_inf() {
     run(&["--", "-inf", "0"], b"-inf\n-inf\n-inf\n");
 }
 
+#[test]
+fn test_neg_infinity() {
+    run(&["--", "-infinity", "0"], b"-inf\n-inf\n-inf\n");
+}
+
 #[test]
 fn test_inf() {
     run(&["inf"], b"1\n2\n3\n");
 }
 
+#[test]
+fn test_infinity() {
+    run(&["infinity"], b"1\n2\n3\n");
+}
+
 #[test]
 fn test_inf_width() {
     run(