adjective. thin in diameter; resembling a thread.
1. Noun, singular or mass In a narrow fin like a gourami's threadlike pelvic fin, this may require a very close look and great attention to detail for you to notice. 2. Adjective To make specimen for museums from veins of gold in quartz, professionals melt the quartz in an acid bath, leaving just enough of the quartz as a base for the threadlike filigree-appearing gold. 3. Preposition or subordinating conjunction All species have long, threadlike antennae and are fast runners.