diff --git a/README.md b/README.md
index 39c516500..1f6b7ce22 100644
--- a/README.md
+++ b/README.md
@@ -36,17 +36,17 @@ To use DDC core, one needs the following dependencies:
 * a C++17-compliant compiler
 * CMake 3.22...<4
 * Kokkos 4.4...4.5
-* (optional) Benchmark 1.8...<2
-* (optional) Doxygen 1.8.13...<2
-* (optional) GoogleTest 1.14...<2
+* (optional, micro benchmarking) Benchmark 1.8...<2
+* (optional, documentation) Doxygen 1.8.13...<2
+* (optional, unit-testing) GoogleTest 1.14...<2
 
 To use DDC components, one needs the following dependencies:
 
-* (optional) DDC::fft
+* (optional, fft interface) DDC::fft
   * Kokkos-fft 0.2.1...<1
-* (optional) DDC::pdi
+* (optional, IO interface) DDC::pdi
   * PDI 1.6...<2
-* (optional) DDC::splines
+* (optional, spline interpolation) DDC::splines
   * Ginkgo 1.8.0
   * Kokkos Kernels fork <https://github.com/yasahi-hpc/kokkos-kernels> on branch develop-spline-kernels-v2