diff --git a/nmap.cc b/nmap.cc
index bad1d53b3..9c3dc9e8f 100644
--- a/nmap.cc
+++ b/nmap.cc
@@ -205,7 +205,7 @@ static void printusage() {
          "  -sL: List Scan - simply list targets to scan\n"
          "  -sn: Ping Scan - disable port scan\n"
          "  -Pn: Treat all hosts as online -- skip host discovery\n"
-         "  -PS/PA/PU/PY[portlist]: TCP SYN/ACK, UDP or SCTP discovery to given ports\n"
+         "  -PS/PA/PU/PY[portlist]: TCP SYN, TCP ACK, UDP or SCTP discovery to given ports\n"
          "  -PE/PP/PM: ICMP echo, timestamp, and netmask request discovery probes\n"
          "  -PO[protocol list]: IP Protocol Ping\n"
          "  -n/-R: Never do DNS resolution/Always resolve [default: sometimes]\n"