'Cunicular' not a word you're likely to use a great deal as a romance writer, although it could well pop up in other types of fiction.
*Michael Quinion says:
'It's better known to biologists than to SF authors. It simply means "rabbit-like". It derives from Latin "cuniculus", rabbit (itself taken from Green "kyniklos"), which is also the source of the old English name for the animal, "coney" or "cony". The Latin word could also mean a burrow, an underground passage, or a military mine. Variations on it appear in systematic scientific names - an American owl, to take one example, is formally known as Speotyto cunicularia because it lives in burrows.
"Cunicular" has occasionally been used in botany and medicine for various kinds of tubular formation. Apart from that, sightings are extremely rare.'
As I said, not a word you're likely to use much, but I thought it was interesting. Besides, it gave me an excuse to post a picture of Peter Rabbit.
*Thanks to Michael Quinion of WORLD WIDE WORDS. World Wide Words is copyright (c) Michael Quinion 2009. All rights reserved. The Words Web site is at http://www.worldwidewords.org