The katakana syllable ヴィ (vi). Its equivalent in hiragana is ゔぃ (vi).

(nautical) a keel (beam along the underside of a ship’s hull) / Short for 竜骨突起 (ryūkotsu tokki, “keel”) (extension of a bird's sternum)

(archaic, humble, men's speech) I; me

(geometry) acute angle