watt / what are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
watt: (noun) a unit of power equal to 1 joule per second; the power dissipated by a current of 1 ampere flowing across a resistance of 1 ohm. (noun) Scottish engineer and inventor whose improvements in the steam engine led to its wide use in industry (1736-1819).
what: NA
watt: w·AA·t
what: w·AH·t
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)