Derivational etymology implying a formal change, entirely ad hoc, but suggested by the synonymy of καίω and δαίω "to burn". Therefore one could assume an etymon with /k/ for a word with initial /d/. The arrows cause damage, therefore the etymon is the cause. The verb is a medium tantrum δηλέομαι but Greek lexicographers always give as the lemma the form of the 1sg active, even when it does not exist. Hence the last sentence "it has two meanings, to make visible and to damage: "to make visible" is δηλόω, "to damage" is δηλέομαι which is a different verb, but the lemma *δηλῶ(happens to be identical with δηλῶ "to make visible"