diff --git a/doc/src/Build_settings.txt b/doc/src/Build_settings.txt
index 87818322fa1b43877ff0fbd184a65c81dd79144f..736e9b9f0e415c75e9b79bdaa0117807fed7e511 100644
--- a/doc/src/Build_settings.txt
+++ b/doc/src/Build_settings.txt
@@ -34,7 +34,7 @@ LAMMPS can use them if they are available on your system.
 
 [CMake variables]:
 
--D FFT=value              # kiss or fftw3 or fftw2 or mkl, default is fftw3 if found, else kiss
+-D FFT=value              # KISS or FFTW3 or FFTW2 or MKL, default is FFTW3 if found, else KISS
 -D FFT_SINGLE=value       # yes or no (default), no = double precision
 -D FFT_PACK=value         # array (default) or pointer or memcpy :pre