This (also aphaeresis) is the process whereby a short unaccented vowel at the beginning of the word becomes lost in conversation—and eventually in general usage.

The matter arose when a student asked how the Latin episcopus came to be bishop. By a coincidence that I pointed out, he had just been reading these lines in Macbeth:

      …his two chamberlains
Will I with wine and wassail so convince
That memory, the warder of the brain,
Shall be a fume, and the receipt of reason
limbeck only: when in swinish sleep
Their drenched natures lie as in a death,
What cannot you and I perform upon
The unguarded Duncan?
     Macbeth, Act I, Scene 7

Shakespeare here is using a colloquial form of the word alembic. Now this is the kind of aphesis where the initial has been taken off and appropriated for use as the indefinite article: such usage, or perhaps misunderstanding, may indeed be the origin of aphesis in some cases.

There is a whole array of words in English where this has happened. Sone examples are:

acute > cute
esquire > squire
around > round
amend > mend
apply > ply
attend > tend
engine > gin
example > sample
annoysome > noisome
opossum > possum
hydropsy > dropsy
escutcheon > scutcheon
establish > stablish
history > story
arrange > range 

For a philologist’s explanation of this process, and the issues surrounding it, see an article by James D. Alexander on the Taylor and Francis website:  https://doi.org/10.1080/00437956.1988.11435781  (click on pdf)

Professor Alexander, who gives the above examples, draws attention to how often this process occurs in speech in Shakespeare, and in other writers: one example he gives is from The Taming of the Shrew:

Grumio: Nay, ’tis no matter sir, what he ‘leges in Latin… (Act I Scene 2)

 Welsh names, he notes, come in for it:

ApHarry (son of Harry) > Parry
ApEvan > Bevan
ApOwen > Bowen
ApHowell > Powell
ApRichard > Pritchard
ApHugh > Pugh

History became story because it was originally stressed on the second syllable; and this same process tells us how to pronounce Ebóracum, which became Jorvik to the Danes (some of whom still think that Yorkshire is part of Denmark) and thus the modern York. The Scandinavian and Germanic languages are all subject to aphesis.

And last week, by coincidence, I passed through the Cheshire village of Spital: a reminder that hospital also was at one time stressed on the second syllable.

But to return to alembic, for which the OED reveals a range of spellings. This is one of those mediaeval words from the golden age of Islamic learning and science*. It is a vessel for distilling, and the Alembic Club at Oxford is for students of chemistry.

It is originally the Arabic al-anbīq, which itself comes from the Greek word ἄμβιξ: a vessel with a narrow neck.

* See also earlier post:  Names of stars