At the core of this root is one move: setting something apart from the ordinary. Do that move to a thing and you sanctify it; do it to your time and you dedicate it; the set-apart quality itself is holiness; the set-apart building is the temple. From the same three letters come Kiddush over wine and the very word קֹדֶשׁ stamped on Jerusalem. Each word below is the act of separation seen from a new side, verified against pealim, niqqud included.
The same root runs through the verb system. Each binyan is a voice: it bends the one idea into active, passive, causative or reciprocal. Tap to hear.
The split is delicate: pi'el לְקַדֵּשׁ makes a thing holy in itself, while hif'il לְהַקְדִּישׁ devotes something to a purpose (time, money, effort). No pa'al is in everyday use for this root; the intensive and causative binyanim carry the load, which is common for abstract roots.
Same root letters, different noun moulds (mishkalim). The mould tells you the function: who does it, the act of doing it, or the thing produced.
Strip the prefixes, suffixes and vowels. Three consonants remain, and the meaning lives there.