From the same as kiyd; properly, something to strike with, i.e. A dart (perhaps smaller that chaniyth) -- lance, shield, spear, target.
see HEBREW kiyd
see HEBREW chaniyth
H3591. kidon
I. כִּידוֺן noun [masculine] dart, javelin (Late Hebrew id.) — absolute ׳כ Joshua 8:18 6t.; כִּידֹן Jeremiah 50:42; construct כִּידוֺן 1 Samuel 17:6; — dart, javelin (distinct from חֲנִית spear, lance, q. v.), בַּכּ ׳נטה (ךׅ ביד אשׁר Joshua 8:18 (twice in verse), compare 8:26; כּ ׳רַעַשׁ Job 41:21 the rushing sound of a dart; וּבְכ ׳וּבַחֲנִית בְּהֶרֶב 1 Samuel 17:45 (weapons of Goliath), כְּתֵפָיו בֵּין נְחשֶׁת ׳כ 17:6 (חֲנִית in 17:7); + חֲנִית Job 39:23 also; וְכ ׳קֶשֶׁת Jeremiah 6:23; 50:42.