The most common and most likely answer to this crossword clue is the 3 letter word ERE
I've seen this crossword clue in The Times
E
R
E
More clues leading to the result ERE
- Before the Revolution devours it
- Before melody is heard
- Old prior to look for an audience
- Perrier has been sampled regularly before, once
- Listened to melody before
- Old prior, as hermit losing a wee amount
- Before dinner eat sandwiches
- Topless just as before
- Before headwear lost its edges
- Wife and husband going where before?
Buddy explains!

The straight part
We know that "Old prior" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case old prior = ere.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 ERE mean?
ERE adverb- At an earlier time.
- Before; sooner than.
- Before
- The organ of hearing, consisting of the pinna, auditory canal, eardrum, malleus, incus, stapes and cochlea.
- The external part of the organ of hearing, the auricle.
- A police informant.
- The sense of hearing; the perception of sounds; skill or good taste in listening to music.
- The privilege of being kindly heard; favour; attention.
- That which resembles in shape or position the ear of an animal; a prominence or projection on an object, usually for support or attachment; a lug; a handle.
- An acroterium.
- A crossette.
- The fruiting body of a grain plant.