diff --git a/src/tcpcheck.c b/src/tcpcheck.c
index 3d99dfd2a..86c798e73 100644
--- a/src/tcpcheck.c
+++ b/src/tcpcheck.c
@@ -3262,7 +3262,7 @@ struct tcpcheck_rule *parse_tcpcheck_expect(char **args, int cur_arg, struct pro
 		}
 		else if (strcmp(args[cur_arg], "string") == 0 || strcmp(args[cur_arg], "rstring") == 0) {
 			if (type != TCPCHK_EXPECT_UNDEF) {
-				memprintf(errmsg, "only on pattern expected");
+				memprintf(errmsg, "only one pattern expected");
 				goto error;
 			}
 			if (proto != TCPCHK_RULES_HTTP_CHK)
@@ -3281,7 +3281,7 @@ struct tcpcheck_rule *parse_tcpcheck_expect(char **args, int cur_arg, struct pro
 			if (proto == TCPCHK_RULES_HTTP_CHK)
 				goto bad_http_kw;
 			if (type != TCPCHK_EXPECT_UNDEF) {
-				memprintf(errmsg, "only on pattern expected");
+				memprintf(errmsg, "only one pattern expected");
 				goto error;
 			}
 			type = ((*(args[cur_arg]) == 'b') ?  TCPCHK_EXPECT_BINARY : TCPCHK_EXPECT_BINARY_REGEX);
@@ -3295,7 +3295,7 @@ struct tcpcheck_rule *parse_tcpcheck_expect(char **args, int cur_arg, struct pro
 		}
 		else if (strcmp(args[cur_arg], "string-lf") == 0 || strcmp(args[cur_arg], "binary-lf") == 0) {
 			if (type != TCPCHK_EXPECT_UNDEF) {
-				memprintf(errmsg, "only on pattern expected");
+				memprintf(errmsg, "only one pattern expected");
 				goto error;
 			}
 			if (proto != TCPCHK_RULES_HTTP_CHK)
@@ -3317,7 +3317,7 @@ struct tcpcheck_rule *parse_tcpcheck_expect(char **args, int cur_arg, struct pro
 			if (proto != TCPCHK_RULES_HTTP_CHK)
 				goto bad_tcp_kw;
 			if (type != TCPCHK_EXPECT_UNDEF) {
-				memprintf(errmsg, "only on pattern expected");
+				memprintf(errmsg, "only one pattern expected");
 				goto error;
 			}
 			type = ((*(args[cur_arg]) == 's') ? TCPCHK_EXPECT_HTTP_STATUS : TCPCHK_EXPECT_HTTP_STATUS_REGEX);
@@ -3335,7 +3335,7 @@ struct tcpcheck_rule *parse_tcpcheck_expect(char **args, int cur_arg, struct pro
 				goto error;
 			}
 			if (type != TCPCHK_EXPECT_UNDEF) {
-				memprintf(errmsg, "only on pattern expected");
+				memprintf(errmsg, "only one pattern expected");
 				goto error;
 			}
 			type = TCPCHK_EXPECT_CUSTOM;
@@ -3346,7 +3346,7 @@ struct tcpcheck_rule *parse_tcpcheck_expect(char **args, int cur_arg, struct pro
 			if (proto != TCPCHK_RULES_HTTP_CHK)
 				goto bad_tcp_kw;
 			if (type != TCPCHK_EXPECT_UNDEF) {
-				memprintf(errmsg, "only on pattern expected");
+				memprintf(errmsg, "only one pattern expected");
 				goto error;
 			}
 			type = TCPCHK_EXPECT_HTTP_HEADER;