Abbreviation of エレキテル (electricity). Rare standalone use; mostly found in compounds or older contexts.
See also: エレキテル
He plays electric guitar in a band.
In old documents, エレキ appears as an abbreviation of エレキテル (electricity).
Common abbreviation of エレキギター. Used in casual conversation and music contexts.
See also: エレキギター
He is good at playing the electric guitar.
I play electric guitar in the band.
エレキテル is the historical full term for electricity (an Edo-period generator), whereas エレキ is its now-rare abbreviated form.
For electricity, a clipping of エレキテル, borrowed from Dutch elektriciteit; for an electric guitar, a clipping of エレキギター.