The tunnel is 4 miles 628 yd. long, and is the longest tunnel on a British main-line railway, and the longest sub-aqueous tunnel in the world.
Source: wiktionary
Sub-aqueous
Synonyms for "sub-aqueous" (18 found)
Ranked by relevance and common usage.
Closest matches (4)
Strong matches (5)
Related words (9)
Adjective(2 words)
Adjective(3 words)
Sample sentences
2 total sentences available.
[...] he'd been hoping to build a bridge over the River Nova in St Petersburg. The Russians would eventually decide to go under the river, but not before Brunel had shown the way, by building the first sub-aqueous tunnel in the world.
Source: wiktionary
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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.