means A short, flat-bladed implement you grip and pull through water to propel or steer a boat, or by extension any similar flat tool used for striking, stirring, or pushing.

from From Middle English 'padel,' a little spade-like tool for cleaning a plough — the early sense was scraping and digging, not rowing. The watery meaning came later, the blade migrating from soil to stream. Its deeper roots are murky; it may be related to 'spade' and the family of words for flat digging tools, but etymologists won't swear to it. The 'wade about in shallow water' sense of paddle is likely a separate word entirely, possibly imitative of the slap and splash of feet.