The most common and most likely answer to this crossword clue is the 4 letter word ALSO
I've seen this crossword clue in The Guardian
A
L
S
O
More clues leading to the result ALSO
- Further a London orchestra
- As lute starts, organ starts too
- An orchestra's on top of that
- Article like this enthrals learner as well
- A London orchestra too
- Seconds from parching, planters use borehole as well
- Royal Society will host this too
- Blocking prodigal son too
- Too early? Stop regularly
- Too restricted by ceremonial sometimes
Buddy explains!

The straight part
We know that "as well" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case as well = also.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ALSO mean?
ALSO adverb- (focus) In addition; besides; as well; further; too.
- To the same degree or extent; so, as.