The most common and most likely answer to this crossword clue is the 8 letter word WORMHOLE
I've seen this crossword clue in The Times
W
O
R
M
H
O
L
E
More clues leading to the result WORMHOLE
- Line up digger capturing hydrogen in small tunnel
- Connecting tunnel in theory hard, without right tunneller around
- Without room, difficulty finding shortcut in theory
- Evidence of boring old empty room’s incomplete
- Sound around shape initially absent in hypothetical tunnel
- Soldiers needing minute to enter inviolate spacetime shortcut
- Underground tunnel undamaged when penetrated by soldiers — 1,000
- Space-time connection found in the garden
Buddy explains!
The straight part
We know that "Connecting tunnel in theory" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case connecting tunnel in theory = wormhole.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 WORMHOLE mean?
WORMHOLE noun- A hole burrowed by a worm
- A hypothetical shortcut between two points in spacetime, permitting faster-than-light travel and sometimes time travel.
- A location in a monitor program containing the address of a routine, allowing the user to substitute different functionality.
- To make porous or permeable through the formation of small holes or tunnels.