I think you are
Antidisestablishmentarianism - and each "an" contains an additional "a".
TI (Texas Instruments) as suggested by GentlePurpleRain in the comments.
a basic verb,
a stack exchange,
Tab (in code styling, tabs are often set to four spaces)
a core muscle,
and some black goo.
I have more, but I risk giving myself away too easily.
It is 28 letters long.
Antidisestablishmentarianism is a political movement that developed in 19th-century Britain in opposition the Liberal Party's efforts to disestablish or remove the Church of England as the official state church, thus being the great English debate, credit to ArnaudMortier.