Where does “sig” come from?

sig (Old English) comes from Proto-West Germanic sik, from Proto-Germanic sīką, from Proto-Indo-European seykʷ-, from Proto-Indo-European sey- — to be wet; dribble; run; to stretch one's arm;...

Ancestry of “sig”, step by step

Step	Language	Word	Meaning
1	Proto-West Germanic	sik	himself, herself, itself, themselves, oneself
2	Proto-Germanic	sīką	trickling water; a dribble; a slow brook; a...
3	Proto-Indo-European	seykʷ-	to moisten; to filter
4	Proto-Indo-European	sey-	to be wet; dribble; run; to stretch one's arm;...

Every word from Proto-Indo-European sey- →Every word from Proto-Indo-European seykʷ- →Every word from Proto-Germanic sīką →