scalar / scaler 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. 👇
scalar: (noun) a variable quantity that cannot be resolved into components. (adjective) of or relating to a musical scale. (adjective) of or relating to a directionless magnitude (such as mass or speed etc.) that is completely specified by its magnitude.
scaler: (noun) an electronic pulse counter used to count pulses that occur too rapidly to be recorded individually.
scalar: s·k·EY·l·er
scaler: NA
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)